As reported in Book - Deep Work.. 3 Rules for Focused Success in a Distracted World, Csikszentmihalyi's research on flow states revealed that working is actually easier to enjoy than free time.
Empiric data showed that people were both happier at work and less happy relaxing than they had anticipated. A strong link between flow experiences and life satisfaction was found. As jobs behave like flow activities, having built-in goals, feedback rules, and challenges, they are easier to enjoy than free time, which needs structuring to be enjoyable.
Newport uses this to argue that not only Deep work is an effort that creates new value, improves your skills and is hard to replicate, but also leads to a more satisfying life overall.
Everyone knows the struggle of having nothing to do after a phase of rigid structure is actually really stressful, even though we were looking forward to it for so long.
In Video - The problem with most productivity advice, Matt Davella interviews Greg Mckeown (author of "Effortless: Make It Easier to Do What Matters Most"). Mckeown points out that "Insecure Overachievers" are actually bad at the process of resting, making it easier for them to find satisfaction in their job (and in turn leading to overworking and burnout, as they avoid resting).
Can this be linked to retirement depression? Tim Ferris tackles a similar issue, and the idea presented here feeds into Multi mini retirements spread across your career might be better than saving up for a big retirement at the end