It was always a mediocre show, but was so massively popular at the time that any criticism was quickly drowned out and brushed away. But now the hype has died down and people are more openly talking about the show’s flaws.
I personally thought it sucked back when it was new and have no interest in watching it now. I watched a handful of episodes as it had a syndication spot on my local networks, but just never got into it. (For the kids: Growing up on the East Coast, the dinner hours were generally news and 8-11 pm was “prime time” when new episodes of shows would air. In between shows would air reruns in syndication. So Friends was the filler I’d sometimes watch while waiting for the new shows to air.)
It just wasn’t funny. It was a group of obnoxious young adults in apartments mugging for the camera while the laugh track assured us what they said was funny (it wasn’t.)
The only episode that landed for me was the boys trying to move a couch upstairs with Ross shouting “PIVOT!” Otherwise, nothing really interesting happened. The “Smelly Cat” song everyone memed about was just grating.
And I remember what was popular about it was Ross and Rachel. Which is mind-boggling, because they were both incredibly toxic and spent half their lives arguing over whether Ross cheated on her. Why would anyone root for that?