The pickle rick episode is obviously about how rick does all this crazy crap because he's trying to do anything possible to avoid his feelings but the whole show is quite obviously about the same thing. The whole show is about how even tho he's got near godlike powers, his real nemesis is himself and his own egotism, which is a defense mechanism to help him avoid feeling grief and loss, and he can sometimes kind of recognize part of this but he can't really accept it about himself or overcome it long term. That episode is just the most explicit about it.