Why do my house home electrical plug sockets spark when inserting a plug?

the wireing is almost 2 years new using gfci sockets. it seems to happen when the appliance is already on. my hot air pop corn popper does not have an on off option. also pluged in my vaccum already on and sparked. im guessing its arking but should i be conserned for safety?
Update: *
wow billy goat. anyone ever tell you if you dont have anything nice to say then dont say anything at all?
"Pobodys nerfect"
way to be a douch.
6 answers 6