Another one down

Life and obstacles. It's like a highway with rolling hills. And sometimes there is a long steady upward slant with a steady progress. Sometimes it's a fast or slow downward slope, at times expected. But the worst part of the road is when there's a mirage on the horizon, like a swimming pool and cool drink in the desert. But just when you get there, you see it was a mirage and the road goes down down faster than you expected. What the hell?