I'm not too sure why this popped into my head. It could just be my positive world view. Anyway...

You know you're an asshat when...

...you take a taxi to the entrance of a mall, pay your fare, then tell the driver that you'd tip him if you had more money.

...do not feel obligated to use directional signals when driving around your suburban hometown.

...upload fansubs to a site that has the raws of said fansubs, fail to delete those raws afterwards, then complain that it's full.