[Jorge]

I think attitude has far more to do with depression than one's job or circumstances.

I've worked many jobs in many fields from floor sweeper, to Electronics Technician, clothing manufacturing to the Aerospace industy.

And I was happy in jobs that other people absolutely hated.
Mostly because I practice thanking God for whatever job I have and always try to excell no matter what the job is.
I also refuse to feel sorry for myself in adverse circumstances and don't allow myself to be occupied with negative thoughts for long.
As a man thinks in his heart, so is he.

[decimon]

...I have and always try to excell no matter what the job is.

In many jobs you are punished for that.