Over bites do tend to seem more acceptable because: 1) The correct jaw position IS technically a slight overbite, so one that's a little too big tends to go unnoticed vs jaws that line up completely wrong, and 2) It's easier to fake proper occlusion.
Now, I have both an underbite and an open bite, as well as a cross bite (so my bite is open more on one side than the other. My first ortho was a miracle worker that she was able to hide it well. The underbite isn't so bad, but the open bite is a problem. In fact I think open bites are the absolute worst, and are even more in need of correction than underbites, because of the extra wear on the rear teeth. Plus my right anterior side of my mouth gets more wear, because it's the side that comes CLOSER to occlusion and it's what I use to bite and stuff.
Day to day I don't have pain besides some TMJ and popping. Most of my frustration tends to come from not being able to do certain things because my teeth don't occlude, for example, holding thin things in my teeth, biting thin foods, completely biting through sandwiches and stuff with my front teeth, not being able to nibble my GF's ear (too TMI?).
Though I am a frequent migraine sufferer and am tempted to chalk it up to my jaw. Plus episodes of ear ringing.
But yes, it can be both a serious pain physically and mentally sometimes. And it's something that needs fixing. It's literally my one obstacle to a healthful mouth. Though my parents seen to think otherwise, and for the longest time kinda discouraged me from seeking treatment. I think it's time to show them the animation I saw of the erosion/wear of teeth in an open bite mouth that convinced me to seek treatment ASAP.