Everything I love will one day end. Why start?
CYNIC
Oh, great, another existential crisis over coffee. So you never eat a pizza because you might finish it? Newsflash: everything ends, including your whining. Start, enjoy, then watch it rot - that's the deal.
STOIC
All things pass; that is their nature. But to refrain from love because of its end is to refuse life itself. The value lies in the process, not the outcome. Begin, and let the end be a teacher, not a tyrant.
ABSURD
You are a sentient ship of Theseus, paddling a river of instant noodles, and you ask why start? Because the paddle is made of laughter, and the noodles are time. Start, stop, start again - the river doesn't care, but it dances.