I try not to let bad drivers or stupid people in general get me all worked up. Just isn't worth it. Tailgaters? I gradually slow down and they usually change lanes. If not, I change lanes.
But let's talk about tailgaters since you brought it up...
Some (many) are clueless drivers that I think should have their driver's license revoked. Bam, I said it. I see it every day, we all do. How do these people think it is safe? The answer is THEY DON'T THINK while driving. Very scary.
Then there are the tailgaters that are always in a hurry. These people may pay more attention to driving than the non-thinkers, but they rarely get anywhere faster than the rest of us.

These people think they are great drivers and therefore can tailgate because "they can hit the brakes super-duper fast if they need to." Yeah right. Just like a race car driver can hit the brakes really fast too, right? Well... it doesn't always work out.
I would love to see anyone come on here and defend the practice of tailgating while driving, that would be hilarious!