They don't ussualy tailgaite you to piss you off, but if they are in a slower lane, they choose to follow a preformance car because they think you are going to speed. And because you follow the speed limit they get frustraited and begin to up it to tailgaiting instead of just following, and they just wait for you to speed up.

Alot of wankers out there are like that, in the end there stuck in a slower lane while you just cruise past them