Depends entirely on the game. Some games, headshots are a major aspect of play, and the mechanics reflect that. TF2, Borderlands...Head Shots are extremely important. In other games, particularly more realistic games (Please lets not get sidetracked on the word realistic...), headshots are not as relevant, and the mechanics reflect that. Any strategy is legitimate, since the nature of play is trying to find the best, most winning strategy. If it works, it works. Sometimes, a game's mechanics are broken, and a headshot is either too powerful, or not powerful enough. That can lead to frusteration, like many would argue in regards to Counterstrikes AWP. But I would say that in TF2 especially, the snipers headshotting ability is taken into consideration within the game. If he wins with a body shot, thats still a kill. The game encourages headshot with bonus damage, but because TF2 is so well balanced, there's no reason to feel bad about a body shot. Your punishment is not shame, your punishment is greatly reduced damage to reflect you less skillful shot. Because when he hit you, his lack of skill was reflected as less of a chance of killing you. And he got a little lucky, which is an integral part of the game. If he killed you with a body shot after knowing that a body shot would be enough, then he made a rational decision to not spend more time trying to get a headshot, and was rewarded accordingly.