I failied to make a graph, but let me explain it.
On the left is recreational riders
On the right is performance riders
At the top are good condition riders
At the bottom are poor condition riders.
Bottom left is small time commitment
Top right is large time commitment.

Here is an hypothesis:
A newbie would be in the bottom left. A pro racer would be in the top right.

As you move from Recreational to Performance your mood increases unless you move too fast. As you move from bad physical condition to good physical condition your mood is better unless you move too fast. At some point you reach diminishing returns and do not gain better mental outlook. The closer you get to perfection the more danger you get of having a bad mood. Unless your goal is to be the best you can be. And realize that max time commitment to the bike will cost you in most other areas. IE if you are willing to pay the price you can approach perfection with a good mood. But this only comes if you have counted the cost and are willing to pay the price.

Edit: A maintenance of what you have maintained will keep a good mood. While neglect of your progress will hurt your mood. So for each person there is an optimal point to be reached along the graph.