Twenty years ago I was a 25 handicap on a golf trip with 16 guys. I knew 8 of them before the trip. I'd broken 90 twice in my life to that point with two 89's. First four rounds of the event were in the 90's -- good for me. This was a by-the-rules event to "protect the field."
Then we went to Mt. Woodson (outside San Diego), par 70, short and tricky layout. My cart partner was an older guy with some health issues. The course was so wet that, even with his disabilities, it was cart path only for us. I found myself being his "caddie" and running back and forth to our cart to fetch him a club, look for his ball, spot a yardage, and essentially drag him around the course. I had not hit my woods well at all those first rounds so I teed off with a five iron all day. Played well. Managed to keep the ball in play. Seemed to hit a lot of greens. Made some putts. Made one birdie. Lagged very well. Never any pressure. Felt like I might really brake 90 -- maybe even a 85. But I was not keeping score and the guys in the other cart (good friends) said I should just play. They'd let me know my score at the end. Again, I was very focused on helping my cart-mate get around without killing our pace of play.
As we walked of the 18th green, I was informed that I had indeed shot the round of my life -- 75!
It was three years before I even broke 90 again. I shot 95 that afternoon on the same Mt Woodson course. I managed to hang on and win the event that week after that net 55. That 75 was simply one of those mornings.