The joke is that SNL was at its best the years you watched it as a teen. I have literally been watching it since it started — Yes, I am old — and I kinda agree with that. SNL is really such an uneven thing that even back then there were good and bad parts of the show. (Usually anything after the second musical performance is throwaway). As well, SNL is best as much for individual performers as it is for the entire show. From Catherine McKinnon all the way back to Gilda Radner, there have been individual performers who made a good show great. (My favorite of all time is Bill Murray, but there are too many to mention here).
For another take on it, here is a someone more objective study on when SNL was at its peak. According to this piece in OpenCulture, this YouTuber took a systematic approach to deciding the best of SNL. He…
… decided to withhold judgment on the overall quality curve of Saturday Night Live, his favorite show, before putting in the time and effort to watch at least one episode from every year in its run
The article has a link to his YouTube results. As OpenCulture concludes,
He may not change anyone’s mind about the best, and worst, seasons, episodes, cast members, and hosts. But he does demonstrate an admirable willingness to dig into SNL’s history and give years of comedy positively antiquated by 21st century standards a fair shake.