For me it has to be Breaking Bad. Because both Friends and GoT have bad seasons. Friends for me lost its luster after season 4. It was great from mid season 2 till the end on S4. But after that quality did fall. Seasons 5-7 were still ok, while the last 3 were bad.
As for GoT, funnily enough it was also at it's best until the end of S4. After that s5-7 were still decent. S8 was an abomination.
Breaking has only 5 seasons, but none of them is bad. All are good with their own properly crafted stories and real thought process gone into how every action would affect the rest of the show.
But I will admit that because of BB being a serious show and because of the length of episodes and the continuity, I will pick Friends if I'm looking for something to just randomly watch and enjoy. I first watched BB in 2014. After that I thought about rewatching it many times. Finally started rewatching in Jan 2020, but I still haven't completed, because it requires real attention and time. Friends meanwhile I have seen 3 or 4 times.