For a lot of guys (and I'm guessing more than a few women), Alison Brie and Jennifer Lawrence are a lot of fun to watch based purely on superficial merits. Subtext: They're hot.
When you tack on that both are genuinely talented actresses, everyone should be very glad that they didn't end up starring in Muffy the Vampire Slayer (sounds like a porno, I promise you it's not) years ago because, as you'll see in a second, it would have done no good for either of them.
Muffy was a show commissioned by Comedy Central in 2007 that basically revolved around a high school girl who killed supernatural beings while being, it looks like, perpetually stupid. As part of the "twist" it's filled with sex puns. Imagine Buffy the Vampire Slayer set at the O.C. high school and directed by Friedman and Seltzer* and you've got the idea of it. The pilot was shot and almost aired, but thankfully the TV gods made CC came to their senses and realize the show would have been a catastrophe.
I can't embed the clip here, but thanks to MTV News you can check out this link:
and see a clip in all its horrifying glory. For bonus points, notice H. Jon Benjamin is in it as the unlucky janitor.
*Friedman and Seltzer, for those lucky enough not to be aware, are the directing team behind, among other terrible "films," Date Movie and Epic Movie. Both of these could be candidates for "so bad they're fun to watch" except they're not fun. They're just bad.