As someone that works in customer service a few things that really get me going would be, customers that think if they tell me there able to get a better deal somewhere else and want me to take money off without proof of this deal then stand there demanding i match or beat a deal when i know there is no such deal and if there really was this great deal then why the fuck are you standing here talking to me about this great deal and not going and buying that deal instead (i work in a store that does shit pretty cheap as is and it is impossible for me to mark something down further then it is without proof or if it is already on sale).
Another one would be the parents that try to by R18 games for there kid that i have just turned away even though the law here is very strict and prohibits the sale of any restricted game or dvd to anyone who is under the age or is knowin to be buying for someone under the age and my counter clearly has signs pointing this out and mentioning the 250k fine that it carrys for companys and the 10k for the buyer and seller.
and last thing that winds me up would be raid leaders that fail at leading the raid group and then rage at people that fuck up when there leadership is clearly part of the issue at hand