Season 3 is bad because Dan's divorce affected him so much that he hired no one other than a load of inexperienced female writers who worked on shitty comedy sketches and the Annoying Orange show.
Why do you think that chink shrink "beat" Rick in the argument? Because, guess what, the shrink is the episode writer's self-insert who just wanted to look more intelligent than the smartest man in the universe.
The other problem with this season is how the main characters just focus on how shitty they are as people and have their most pathetic attributes flanderized to death instead of, y'know, improving themselves through actual character progression instead of "dude nihilism we all suck and we're all gonna die lmao".
There's also the problem with Summer being such a hypocritical asswipe. She was slobbering over a half-naked dude in a fucking done-to-death Mad Max universe, yet somehow, the guy who dumped her so he can go on a date with a much nicer person who isn't such a basket of anxiety and has a great figure is somehow justified to have his mortal existence permanently ruined by an out-of-character Morty.
Season 3 sucks ass, it doesn't have any of the entertaining charm Season 1 had.