When I look back at pictures of myself serving as a US Marine, I remember those days as being mostly good. I was young, doing something that had meaning, and surrounded by friends.
But the truth is that, if I remember hard enough, those weren't my thoughts at the time. In my mind, I was always complaining, "why am I here" or "this is dumb." And normally, I was wishing I was somewhere else.
Most of us live our lives by trying to put our minds somewhere else when we go through difficulty, and that's a huge mistake. It's a mistake because there is so much opportunity to be had just by living in the present.
Stop wishing you were somewhere else, bring your mind to the present, and you'll be amazed at what you can learn.