wow.. good questions.. first of all cocaine is a man-made chemical and personally i don't do that.. i've seen the destruction man-made chemicals do to people and... NO THANKS.
also, the hairs are simply pistils which are like the genitals of the female plant. they will catch pollen and it will slide down into the calyx where the process will take place to create a seed. all smokable marijuana should have those little hairs reddish orange hairs. they start out white first.
marijuana is very nuanced in the sense that it will do different things to different people AND different types of marijuana will do different things as well AND the amount you use will also do different things. i will be as thorough as possible so this will get long...
the different people issue is more of a personal thing. it depends how you're feeling at the time, your mood, experiences, reasons and so on. this is why some people can say they don't like it. some people don't like the feeling of being high. you might, you might not.
as far as the types of marijuana, there are really two kinds - indicas and sativas. indicas are usually the marijuana that you will see the most because it has a faster grow time than sativas by almost a month. so if it's faster they can sell it faster. why is that important? it's because indicas are the type of marijuana that RELAXES you. this is what prohibitionists portray in commercials to make you believe that marijuana will make you lazy. since indicas are more prevalent in the US, most people who smoke will act lazy. anyway, this is also what's good for pain and nausea as well.
then you have your sativas. these are a bit harder to come by. but if you got some, bless the heavens. this is the marijuana people talk about that will help you focus, give you clarity, energy, and the infamous creativity. it does truly exist, believe me. sativas can also be a good aphrodisiac as well.
next you have the hybrids which may contain a split of indica/sativa. there's no real way to tell the exact concentration of the split outside of testing it yourself. growers prefer hybrids because it's a way to include sativa with the quick grow time of indica. depending on what you get, you will have different feelings from it. literally, even two seeds from the same mother won't grow the exact same plant. one can easily be different enough from the other to make a difference.
now we come to the amount used. you can get buzzed, high, or FUBARed. buzzed is when you've smoked a small amount and you're just barely feelin it enough to know. buzzed on indica is good for calming down. buzzed on sativa is good if you just want to focus on the task at hand.
gettin high is when you've smoked a very good amount. high on indica is sleepy time. that's why it's good for insomniacs like myself. high on sativa is the creative zone all the way. this is where your mind is truly activated.
FUBAR or "f'd up beyond all recognition" is where you've simply done A LOT. it's never dangerous but it can be one hell of a ride. FUBAR on indica is pass out time. you can really get into a nice comfortable deep sleep. make sure you do this alone because people like to draw on your face and stuff and you won't feel a thing. but it takes a lot to get there and unless you're on a mission, it's a hard to get FUBAR on indicas since you'll be asleep before you get there lol. FUBAR on sativa.. OMG.. awesomeness. i've been on that cloud only twice. let me tell you, EXTRA SENSORY PERCEPTION.. you will not just hear things but you'll be able to focus on them. like if the tv is on, you'll hear someone kick a can outside. you'll be able to tune out the tv and focus on the noise the kicked can made and be able to tell exactly where it is. it's definitely a most amazing feeling. you will notice things you haven't noticed before. you'll be in a world of true clarity. i think it's like nirvana almost. this is where light hallucinations happen.
personally, it was pink flashes of light and bunnies the first time. the second time, it felt like God was hitting me in the forehead with a hammer. but there was no pain. instead there were waves or vibrations emanating from the center of my forehead to the back of my head. it felt like a deep tissue massage in your brain. i just closed my eyes, enjoyed the vibes, and smiled.
as far as what you wanna do... it depends on what you wanted to do from the beginning, from before you started smoking. a lot of people believe marijuana makes you want to do stuff, crazy stuff and that's not true. i'll admit, it will make you want to eat BUT, marijuana isn't going change you so much that you want to jump off a bridge or go kill someone. that's never happened and i can safely say there are absolutely zero cases of such situations. if someone tells you there is one, do the research. most likely you'll find they mixed the marijuana with something harder (like cocaine *ugh*) or took something completely different. anyway, if you've got work to do, indicas are a terrible option. if you want to relax, sativas aren't going to help. if you don't have access to what you really ought to have, then don't even bother smoking. it's not worth it.
one topic that needs some clarification is the actual age of marijuana at harvest time. marijuana is best harvested when the trichomes (lil microscopic crystal balls on top of the stalk) are cloudy to amber. they first come in very clear, turn cloudy, and finally turn amber or brownish. if marijuana is harvest too early (clear trichs), it can produce an "up-high" which is more sativa-like. the problem with early harvesting is that the marijuana isn't fully developed so you lose out on quantity. if you harvest marijuana late (amber trichs), it produces more of a "down-high" which is like the indicas. but the potency diminishes. most people can just eye good weed from a distance. but if you're a serious connosieur as i am, you'll get a pocket microscope ($10 @ radioshack) to inspect down to the trichs and know if you've got good S**T.
now mexican marijuana suffers from this scenario heavily. i am not being biased, just an honest marijuana user. they simply don't care for their marijuana properly. first of all, they don't do anything about pollination. if the marijuana plant is producing seeds, it's wasting energy that could be used to produce MORE thc. so you have a lower potency plant. then they over dry it and brick it all up which further diminishes the potency. then the actual time it takes to get to you will also affect it's potency. if you're in a border state, mexican marijuana can be awesome because it is a sativa. they grow metric tons of this stuff so it's damned cheap too. but that's only if you can get it FRESH. once you're further north, mexibrick weed loses it's potency as well as it's sativa high and goes up in price. this is why i don't smoke it anymore.
but being that mexican marijuana is the most prevalent in the US, you get even more people who seem lazy because of its age and lack of proper or appropriate care. HOWEVER, it is good for first timers because it isn't so potent that it will make you uncomfortably high or too high your first time.
also the giggles will come depending on the situation. if you're with friends or maybe just watching a comedy, even the dumbest jokes will have massive appeal to you. in some cases, even non-jokes will have massive appeal. for example, i was with friends, about 7 of us. my friend was flipping through the channels on tv looking for a movie. my eye caught the funniest face as he flipped thru cspan during a congressional hearing on steroid abuse in baseball. this guy was obviously so bored, you could really see it. while the gentleman at the table was talking, this guy sittin behind starts nodding off and falling asleep. but it was just the process of it all that had us all literally in pain from laughter. if i wasn't high, i wouldn't have caught that so quickly.
edit 2 (lol, i can't sleep, im out of weed.. see what i mean by insomniac lol)
the marijuana i used to get FUBARed twice was mexican marijuana. the first time it was a godfather which is a cigar that is emptied - not cut and gutted like a blunt - and then refilled with marijuana. basically it was about a half-ounce (~14g) of mexibrick packed into a cigar. the second time was about a 2g joint of some very fresh mexican marijuana. i won't say where it came from, it was just very fresh. and i've never been anywhere near mexico.
let's just say i am not your typical everyday stoner.. i am well versed in the way of the weed LOL.