What is the appeal of bad television?

I’ll probably encounter a few dissenting opinions, but in general, what makes television shows that are unequivocally bad so popular? CSI? Fringe? NCIS? Two and a Half Men? Big Bang Theory? Grey’s Anatomy? Add more if you like. Even if these shows had something going for them once, they currently reside in the dregs of hackneyed, predictable, uninspired routine, and yet they consistently pull in big ratings. What gives? Is there an appeal to bad television or do people just watch whatever is presented to them?