I am a relatively new golfer. Most of my experience is from a smaller golf course in my hometown. I recently moved to a new state and started golfing every chance I get. I typically only get one day off a week so I like to go golfing to get away and be alone for a few hours.
Since I go alone I often get asked if I want to jump in with a group, just random people either in front or behind me. I have chose to join some but mostly i will decline.
Today I had an experience where a guy asked if I wanted to join in with he and his friend. I politely declined saying I just wanted to go alone. I got a bit of grief from them for declining. I originally chalked it up to them being rude but then I got to thinking, an I violating some sort of golfing etiquette without knowing? I do often get some kind of negative reaction from people when I decline.
As I said, I used to only play on very low volume, lower quality courses so I rarely ran in to any other people. I am always nervous of breaking any unwritten rules when I go to larger and popular courses.