Dang, I thought spitting sun flower seeds was just a baseball thing that benchwarmers did.
Seriously, I've never seen a golfer throw a handful of seeds in their mouth to work through on the course and always blamed some random birds for leaving spent seeds on the green. lol.
What irks me;
Golfers that don't repair their divots and those that ignore larger pitch marks on the green (even if you didn't put it there).
Unfortunately music has become commonplace so I just grin and bear it but if I can hear your music from the next fairway, you're being downright rude.
Paying a hundred bucks + for a round and then being charged another $7 for a small bag of range balls.
Courses that do not have any drinking water, especially during the summer months.