First season was directed by Frank Darabont who is awesome at making great movies from written works of art. Then AMCunts saw this and fired him after awesome season one and replaced him with Glen Mazzara who never made anything worthy of note. They also doubled the number of episodes for same content and requested that more episodes are shot indoors to make everything earn more money. And it fucking worked.
I stopped watching when they introduced horrible CGI and fake gun effects (no knock back, no shell ejection, no slide movement).
I'd argue the first few seasons - apart from the horrible acting from time to time, and prolonged passages just to stretch time, and filler episodes, and dumb people, and...
I was with them up to the end of the second season with the farm.
After that they fell into the cycle of characters having to be excessively stupid to inject drama.
I stopped watching at the point where they pretended Glenn was dead, but he was actually hiding under the bin. Not because it was a cheap trick, but mostly because that was the point where I realised I no longer cared who was alive and dead.
I stopped watching when Glenn finally died. Mainly due to the fact that I found out through social media because I missed the first episode of that season when they revealed who got beat with Negan's bat, and everyone on social media ruined the reveal.
He was my favorite character, and I know in the comics he dies much earlier than in the show, but I lost interest after that.