Will smoking marijuana once have permanent effects?

My friend smokes it sometimes and he offered me some. I'm not sure if I want to try it, but I was wondering will it have permanent effects if it's smoked just once? Like, I heard it can alter your personality and stuff, will it do that if it's done once? If I were to try it, the main reason would be... show more My friend smokes it sometimes and he offered me some. I'm not sure if I want to try it, but I was wondering will it have permanent effects if it's smoked just once? Like, I heard it can alter your personality and stuff, will it do that if it's done once?
If I were to try it, the main reason would be so I could tell my friends who want to try it, "Don't, it's not worth it, trust me" or something like that.
Also, I've never touched a cigarette in my life, so I have no idea what its like to smoke...
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