I apologize, never was a gross exaggeration. I almost always bring enough water. But then there are times you don't... I've obviously never misstepped enough to die or suffer serious dehydration. But for safety you'd need far more than enough, right? If you go off trail suddenly enough becomes half what you need. Or you get hurt and can't move well. This is where the water typically becomes not nearly enough.
If you're really that bad at estimating water needs bring 2x as much as you think, dump out the extra half way into the hike.
This is the attitude that causes people to burn down forests in panic mode.
If you're constantly out of water on trail, I heavily recommend taking up another hobby, like crocheting.
Had more than enough for things going good, not enough now.