The persona of any memoir, like an online persona, is always constructed and filtered to some extent, and given that memoirs get polished, are presumably filtered and constructed more.

If I could give memoir-writers a single tip on how to do that, I'd say, "Don't forget that you have to be interesting to the readers, who are not inherently fascinated by you already. You have to make them interested by leaving out the boring and annoying bits."

I'm not sure that the persona has to be likable, though it's definitely a plus. But the persona has to be interesting and enjoyable to read about.