David Wain's romcom parody is so much better than it has a right to be. I would say that it's more than just a send-up of romcom tropes. The self-awareness that They Came Together carries with it through every gag really elevates the comedy for me. And the inclusion of utterly random, off the wall humor (you can say that again) brings the comedy together in a way that turns it into much more than just a romcom parody.
Everyone in this movie is great at playing it straight in the face of absolute absurdity. The movie frequently doubles down on the absurd humor (like the handful of times when Bill Hader and Ellie Kemper react to something in the frame story). Other times, it goes completely off the rails in its zaniness (there's a sword fight sequence and an extended music video montage) to great comedic effect.
The absurd comedy that is such a staple of David Wain's career really isn't for everyone. But it hits my funny bone every time and because of that, They Came Together is one of my favorite comedies.