But that's what makes a theme great. It worms its way into your brain and stays there for as long as you can remember, just like a decent Top 40 hit. Sometimes, if it's good enough, it'll even stick around after a show has ended.
To celebrate all those great theme songs out there, we've partnered with ABC News and put together a poll so that you can vote for your favorite one of all time. Some of these are instrumentals (the Hill Street Blues theme), and some are hit singles in their own right (the Friends theme) – but all of them have proven their lasting influence on pop culture. Some have even been parodied (the opening sequence of Family Guy, which pays homage to the All in the Family theme.)
After you're done voting, make sure to take the rest of the polls on ABCNEWS.com. And tune in for the Barbara Walters-hosted special about classic TV shows, which will air in September and will feature the poll results!