OK, this about the Arcade/MAME games that you regret putting time in to get a score. There are multiple reasons. Like learning the game totally sucks for one.
For me, I have to go with Willow. The game gives you a middle finger on the end of the second stage. Even lots of practice on the cart stage didn't help whatsoever.
So yeah, all the time I spent to get to that part felt like a complete waste of time.
So for you, was there a game you realized that you simply felt like you wasted your time going after a score?