Don’t harbor an exorbitant degree of loyalty to losing strategies. Certainly don’t wind your identity up in them.
You do things, and some of those things work. Some don’t. But who you are doesn’t have to be defined by any particular act or even set of acts. If you switch to a meatless diet for health reasons, you don’t have to suddenly “be” a Vegetarian(tm), especially if later it turns out that the diet isn’t working for you.
Not every challenge is zero-sum, of course. Many aren’t; just because you didn’t succeed at something doesn’t necessarily mean that someone else did, nor at your expense. But maybe a strategy won where yours didn’t, and it’s foolish not to look at that strategy and see what you can take from it.
The biggest thing that keeps people from doing that is identity. They wrap their egos up in a course of action and make it part of who they are, instead of saying “this didn’t work, so I don’t need it.”
Sometimes the circumstances of a choice have near-zero consequences, so you don’t need to care. You don’t have to switch which football team is your favorite just because your favorite team hasn’t won in a while, because it doesn’t matter. But if you’re actually betting, and not just cheering? Cheer for whoever you want, wear whatever colors you want… but bet like the money in your wallet is worth more than which color shirt you’re wearing.