Even when you see some games of GMs, they play until the win is painfully obvious, because there is ALWAYS a possibility of making a last minute slip. If you say you've never lost a totally winning position, you're probably the only one...I'm not pointing out anyone specific, but I know good and well that GMs even play to the obvious end, knowing that the same way they made a mistake, so can their opponent.
Of course, in the end, maybe it is best to respect your opponent, that they don't understand like you do...a queen to a beginner is no better than a bishop or rook, because they don't understand how to use it anyway.
if my opponent gets an advantage early in the game i would probably play on becuase he might slipp in the long game or i can find a great tactic, if he sets me up in the endgame i wld imedietly resign, and if there is a forced mate on the board, or a rook & king vs king then i would play the quickest moves for him to checkmate me, of course in a real life game i would resign, but in chess.com there is plenty of time for every move!