Obsession depression
Like when you're so stuck on one thing you forget to live, and when you finally get it, you're just tired and ready to throw it all away.
He was obsessed with getting into that club, and now he's just stuck there with no friends.
She waited 5 years to get her tattoo, and now it's just a sore and a bad decision.
He spent all his money on the latest phone, and now he's broke and it still crashes.