I remember really enjoying How I Met Your Mother when it was airing. I tried for a rewatch recently and only made it a few episodes in because I was so disinterested. It felt empty, and the humor wasn't hitting. I think it's a combination of I've changed (I've aged out of the "20-something singles fool around in a fantasy version of NYC" demographic) and TV has evolved (good comedy shows are no longer just goofy hijink situations and setups for one-liners).
So instead I rewatched Archer season one (same era as HIMYM) and fortunately that one still slaps.