Unfortunately, I am not one of these people who has seen the show as it aired (which actually applies for most people on here, I guess). So I started watching random episodes that were on TV, and I basically started around the time Monica and Chandler got married, which was reruns of season 7. And then I kept watching up until season 9 before I bought my first season box set, which was season 6 because season 10 hadn’t aired at that time. So I figured I’d go back so idk, bit stupid why I didn’t start with season 1 instead, but I remember seeing random episodes on TV from earlier seasons as well, so to sum it up: my viewing process didn’t have any structure at all. Hence, I knew that Monica and Chandler were together/gonna get married and then basically rewatched their whole story, so the surprise effect sort of got lost on me.
I bet it would have been an awesome experience to have seen it as it aired for the first time; but it also would have cost me a lot of feels, because this way I just knew that they’d end up together. ;)