Happiness and Contemplation

Hello forum,
I have had some consideration about happiness and how it affects contemplation. I think that when I am feeling unhappy or depressed I find it more difficult to do contemplation and stay with the work. I think this has led me to some thought which is like “first I should focus on being happy, and then do whatever else”.

I wonder if when I am happy I am working more intelligently anyway? Or perhaps I am more effective in doing the work when I am happy.

Any feedback on this topic would be appreciated.