We are vulnerable to this fallacy in all areas of our lives. You've surely had the experience of forcing yourself to finish a meal that you've paid for, even when you don't really want to eat any more or continuing to read a book when even after 200 pages you're not enjoying it.
'Vince paid $1000 to an indoor tennis club that entitled him to play once a week for the indoor season. After two months he had developed tennis elbow, which made playing painful. He continued to play in pain for three more months because he did not want to waste the membership fee. He only stopped playing when the pain became unbearable.'
(Misbehaving: The Making of Behavioural Economics, prof Richard H).