I think what happens is, the better off you are, the more the little things annoy you, and if you've had no real distress to compare it to, you blow it out of proportion.
A friend of mine, D, who is quite posh but a decent old stick, said she has a friend X, who's, like, a multi-millionaire, but is always unhappy.
D asked X why she was always so down when she had everything going for her. X's reply was "But my dear, I've got dandelions in my lawn!"