Grargar: Why it's not good? Why would you even need to remove the game from your Steam account?
phaolo: I.. I never used Steam.. aren't they allowed to remove games from accounts for whatever reason, unlike Gog?
Technically, yes. But retailers tend to avoid bad publicity, so while they could simply cancel your license to a game (because that's all you actually buy on steam or on gog), they tend to not do that without a good reason,... or at least as much as they care about that based on their market share.
GOG, unlike steam, stacks the deck against itself, because you can download the game and then keep it in that state for as long as you like, since there is nothing preventing you from installing and plying. As such, taking your license away seems pretty pointless in the long run.