Two things you should never say in a personal essay:
1. I swear I'm not making this up.
I assume you’re not making it up—that’s the implicit pact you’ve made with your readers. If an incident or something someone said seems incredible to you now, let it speak for itself in all its incredibleness. Trust that we’ll buy it. If we don’t, the writing has a problem you need to work on. Promising that it’s true won’t help.
2. I don’t remember exactly, but . . .
If you don’t remember—and no one can recall everything that happened last week perfectly, let alone 20 or 37 years ago—then pretend you do. This is not the same as making it up. It’s reimagining—what your father’s words likely were, or your own, or how things went down that April Thursday. You know yourself and the others in your life well enough that, with hard work, you can do this reimagining, this recreation. (And yes, it’s allowed.)
Readers look for authority in a personal essay. Don’t make excuses for your story. Claim it.