Perseverance is overrated.

If I have to persevere, then I do. It doesn't require inspiration. It's just doing whatever thing is mandatory.

If it's not mandatory, then I take my best guess about the long-term outcome. And if the risks seem to outweigh the rewards, I quit, and do whatever seems better.

I've got a lot of reasons for that, but the primary one is me sticking with my startup for waaaaaay longer than anybody would say is reasonable. Winners never quit, and quitters never win, but those who don't win and don't quit are idiots.