When characters are confused or dumbfounded, their lips droop down their faces. This is an homage to The Ren and Stimpy Show, in which Ren would do the same thing.
Rick's catchphrase "Wubba Lubba Dub-Dub" was accidentally conceived by series creator Justin Roiland who also voices Rick. While doing a recording, a scene was described in the script where Rick would be spinning around on the floor and yelling "Woob woob woob woob woob" like Curly from The Three Stooges. Roiland, who is dyslexic, misinterpreted the line and blurted out "Wubba Lubba Dub-Dub". The makers liked "Wubba Lubba Dub-Dub" so much that it stuck with them. They later decided that it means "I am in great pain. Please help me".
May 10th, 2018: Adult Swim renewed Rick and Morty for an additional 70 episodes. If the show continues in the format it built for seasons 2 and 3, 70 episodes would most likely mean 7 more seasons. This would bring the show's total season count to 10.
Any time a fake commercial appears, they are single audio takes of Justin Roiland improvising as he stutters and laughs throughout them.