Many, many times.
I have a mild motor skill impairment so try as I might, sometimes I just reach a point in a game where I can bang my head against a wall for days and get nowhere, and I just no longer have the time or patience any more to keep playing a game if all it's giving me is frustration and unhappiness, it's just not worth it.
Even some games I really loved I had to abandon eventually; Donkey Kong Country Returns and Tropical Freeze for example are among my favourite platformers of all time, but I could never beat the final boss of either game.