Most surprising move I've seen on a golf course

[Punker]

Myself and two friends play every Thursday, with one of my friends being out several other times per week. On one of his "other" days, he was paired with some random guy (Paul) who was a decent player and a good guy, so they have been playing together on Sundays. Today, me and the other friend both decided to play with them as well.

We arrive at the course to play as a foursome, and apparently the other guy has brought a friend along as well, so now we are a fivesome. Me and one friend shoot in the mid90s, our regularly playing friend low 80s, Paul mid 80s. It turns out the friend he's brought along is a 130ish type golfer, not exactly ideal for a fivesome.

After 2 holes, we are a little slow but the course is quiet so not a big deal. However, on the second green, Paul putts out and then says he is going to tee off on the third to help us keep up the pace. No big deal, there's four of us left to putt out, he can go tee off and we'll spend a little less time on the 3rd tee.

I putt out next and see Paul teeing off, and decide I'll walk over and tee off as well. However, rather than waiting, Paul starts walking off to his ball. Fair enough, I figure, he's just going to walk up to his ball and wait for our tee shots.

Negative - he walks up, hits and keeps walking and we never see him again for the remainder of the round. He leaves his 130shooting friend with us and plays as a single.

Our regularly playing friend was so tilted, he quit the round at the end of the 3rd hole.

Cliffs notes: group of 3 friends plays with a group of 2 friends. One of the twosome plays ahead and leaves the other four behind on the third hole.