Players who don't understand the game. I recently played the course used for the LPGA ShopRite Classic days after the tournament under tournament conditions. They said the grees were a little slower but we couldn't tell. It was humbling as I had played this course many times before. After two holes it was clear this was a different golf course and I understood that my score wasn't likely to be what I am used to carding there. By the completion of the second hole once I got that in my head I had a great time and gained a lot of respect for how hard this game is at the professional level. Bottom line is to have fun and don't set expectations beyond what is reasonable.