I find it quite difficult holding down full-time employment while attempting to write. It's not simply the time and exhaustion factor (though both are significant), it's the stress of being responsible not just for yourself, but others. My job doesn't just support me; other's rely on my income.
After awhile, it begins to feel like a prison, but not one from which you can ever be released. It's the drowning feeling of being caught in a trap, swept by tides not under your control. The pen garners the weight of Sisyphus' boulder - you can start, but never finish.
In our society, I think this feeling of being stuck is rising among all ages. No one wants to feel like they're in a cage.
It's funny, I'm working on a proposal right now that has a pair of characters facing a similar conflict. For them, it's about having chosen duty over dreams. It's a choice that begins to wear at them. Of course, duty is important. The selfishness of just seeking your dreams without regard to anyone or anything else is pretty self-indulgent. Still, hopes and dreams are what makes the prison bearable, right?