Consider, too, where this perception might come from.
We can add some things up:
-The compounds most notorious for causing a quick trigger are highly androgenic (e.g., tren). In addition, clomid makes some folks pretty damn moody, too.
-A BB'er is mostly likely to be on stuff, as well as recognized as a BB'er when he's dieting for a show (looking leaner, wearing less clothes, posing in the gym, etc.), which is when he's (or she's) most likely to be bitchy / an asshole / act like a dick, etc.
So, add a nice contest diet, the training rigors, etc. to make you a bit testy (pardon the pun) to a pre-contest stack of highly androgenic stuff and maybe clomid and you've got a nice set of circumstances for making folks connect steroids with rage.
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Then of course, you've got the asshole effect, like BN and LATS have mentioned. Take an asshole and give him the at least perceived power that comes with being bigger and stronger from taking gear and you've got a asshole with an inflated ego - a bigger asshole... LOL
-S