a number of years ago, in my 2nd US congress tournament, I kept noticing a lady a few boards away who kept getting up from the table and walking around every few minutes. I felt it was distracting even though I wasn't playing her. But mostly I kept thinking to myself, "I hope we don't get paired in later rounds"
We got paired about round 5 or so. Turns out, by that time I had already decided to just play my game the best I could and not allow myself to be distracted further. We had a nice game. I forget now who won. And she's a nice lady (and used to be a regular poster here (and godiscussions)).
I've since learned that there are a lot of people, who for one reason or another have issues they can't help. Bad back and has to stand. Has to go to bathroom a lot. Blind and has to play with face 2 inches above the board (nice guy too). Hands shake and can barely place a stone without disturbing other stones nearby (also a really nice guy). Etc.
You've just got to put it out of your mind and play your own game.
I wonder what bad habits I have that bother other people that I don't realize I have. Of course, if I knew, I might change, or I might exaggerate just to annoy (depending on my opponent, of course)
