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

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.

Part 1 of the "Abbott Elementary" and "It's Always Sunny in Philadelphia" crossover coincided with the midseason premiere of "Abbott Elementary." The shows air on different networks but share the setting of Philadelphia. The episode aired live on ABC on Jan. 8.