Some important parts of life are like video games.
You know the rules, you've seen how others have played the game, but you can't really know what it's all about until you play the game yourself. The longer you play it, the more familiar you become with the rules. You find yourself engrossed in it, involved in it, spending lots of time doing it, learning new techniques, leveling up, just having tons of fun.
But at some point the game starts to become more difficult. You somehow sense that things aren't going too well, so you use your knowledge and adapt your technique to try to survive and win. Still, it happens. The enemies overwhelm you or you've run out of time or the strategy you used backfired or your timing was all wrong or the decision you made wasn't the right one. Sometimes you just don't know what the hell happened: one minute all was going well, the next minute you're left staring at the screen--either hurling expletives at it or frozen in stupefied shock.
You've run out of lives or you failed to save your game at some point. There's no way to regain all that you've achieved thus far. It's really over. And for a moment, nothing else in the world seems to matter.