No matter what happens today, I will find the positive in it.

Finding is the honest verb here. Not manufacturing, not insisting — finding, which implies something already present and slightly buried. A cancelled plan genuinely contains an unexpected free evening. A long queue genuinely contains ten minutes you were not going to get otherwise. Neither of those cancels the annoyance. They sit alongside it, and one is much easier to overlook than the other.

This goes badly when it is used to talk yourself out of a real feeling. It goes well as a second look, taken once the first reaction has had its say. Let the annoyance happen. Then go looking.