Mark Hamill plays Skips. Nobody ever told me that, and I never figured it out because the credits always roll too quickly.
What kept this show so timelessly entertaining is that J.G. Quintel utilizes the power of cartoon animation to subvert the viewers expectations towards the end of every episode. Regular Show's plots are never predictable, and that was the shows biggest strength. If an episode started one way, it's most likely NOT gonna end that way, and knowing that is what gets you excited to watch the next episode, especially near the end of the series when the episodes start playing off of each other for one big reveal that only the fans will cry over.
Other cartoons tried to do what Regular Show has done, but it's never as "insane" and "unexpected". If you enjoy Black Mirror, the endgame of the Phineas and Ferb series, or any other TV show where a franchise goes bezerk and starts to turn on itself near the end of its run, you'll adore Cartoon Network's Regular Show and it's random use of licensed rock songs, natural comedic timing, and kooky but consistent eventually-loveable characters.