I have also stumbled upon this catch—care too much and carry the burden of stress and disappointment, or care too little and find no fulfilment in work. The solution I have found is to practice losing myself in work (achieve flow) and yet not be attached to the result. If it were your checkout line I’d try to be completely focused on dispatching the clients with efficiency and courtesy without looking at the length of the line.

Focused and productive work is a reward in itself. You leave the office feeling energized and the day flies by. The paradox is that by not caring about the result you often produce your best work.