I was once doing well in an over-the-board tournament and then paired with well known Chicago master, Dr Eugene Martinovsky. We had each won our first 3 games.
I was playing Black and on about the 11th move had a slight advantage and Dr. Martinovsky offered a draw.
I knew that if someone offers a draw early in the game, he thought he had the worse of it.
So, I turned down his offer of a draw. [he was rated about 2350]
About 1/2 hour later, I resigned.
surprise!
once i was playing an person in an otb tournament that otb player was mated by me up to 10 times every time he took it back and said i willl kill you if you call the arbiter. he was twice as big as me that time and i also was a sissy that time. at last i lost my temper and called the arbiter. WHILE i was calling the arbiter he changed the position of the peices.the game was agreed to a draw.