TV schedule really started off perfectly with a hilarious crossover of Abbott Elementary and It’s Always Sunny in Philadelphia. However, while most characters from both

The highly anticipated crossover episode of “Abbott Elementary” and “It’s Always Sunny in Philadelphia” blends the raunchy, NSFW style of the FX show with the witty, family-friendly romp.

Here's some background and inside jokes to help fill in some of the gaps for viewers who don't watch both Philly-based shows.