I think Friends was more relatable to non US watchers...and that's why it's an international hit while Seinfeld is mostly (and sadly) unknown outside the US.
I was lucky enough to discover Seinfeld in original version late at night on a paying channel in France but most people didn't have access to that channel (it cost a lot of money but had movies before any other channel).
It's definitely in my top 10 series of all time and my favorite sitcom. The next best would be Himym, then BBT then and only then Friends.
Bottom line:
Seinfeld feels real, Friends is wacky.