Pick beliefs for the purpose
There is no single right philosophy, so treat beliefs as tools. Use different ones for different purposes, swap them as the situation changes, even just for fun. None of them has to be literally true to be useful.
A short book of 27 contradictory chapters, each fully arguing a different philosophy of how to live, followed by one concluding reflection.
Present moment versus lasting memories
One case says only this moment is real, since the past is just memory and the future just imagination. The opposite case says a life you can't remember at the end was wasted, so you should deliberately make memories. Both pulls are real, and choosing between them shapes how you spend a day.
Striving itself makes people happy
Pursuit is the opposite of depression. The people who were happiest with their lives near the end had spent the most time absorbed in fascinating work. Happiness comes from the chase, not from arriving.
Tiny breaks let you last longer
You can do far more push-ups with a ten-minute rest between sets than in one go. Work the same way: frequent short breaks let you keep going much longer than people who push straight through.
Opposite answers can both be true
Advice on how to live often comes in pairs that flatly contradict each other: live for the future or live for now, serve others or serve yourself, stay free or commit. Each one, followed on its own terms, is a valid way to live. Life is a paradox to be experienced, not a problem with one solution.