This week's news about Ugly Betty going off the air for a few weeks while ABC launches a comedy block seems to have a lot of people afraid that ABC is giving up on the show — and, more importantly, that viewers will too. The way many shows struggled to come back after the writers' strike is one sign that people often give up on shows that are off the air for too long.

Of course, that's only one reason people break up with TV shows. Maybe a show starts to explore plotlines you find ridiculous (an argument I've heard a lot in favor of ditching Grey's Anatomy). Maybe it switches nights or times (a complaint I've heard about House now that it's on Mondays). Maybe you hear the network is probably canceling it, so you don't bother getting invested (say, Lipstick Jungle).

So, here's my question: When — and why? — do you decide to give up on a show? Is there a certain number of bad episodes that makes you draw the line? Or are you a person who never gives up, out of hope that things might get better?

Photos courtesy of NBC and copyright 2009 ABC, Inc.