* Figure out a good way not to hire a 2-faced asshole, because it ain't easy to fix.
* Making someone change their normal behavior may deplete their energy in the short-term, and they'll come off as fake. So, if you're after that, go full on Pygmalion, and give it some time to set in; some crap two-week HR course won't cut it.
* Be yourself. It's less work and you'll come off as more real.
i.e. I speak up much earlier than I used to, when I thought it'd be 'mean', preventing things from deviating so far from my comfort zone that eventually I need to address everything I was uncomfortable with, all at once.
It's hard, you just want it to be a small infraction and then everything will be fine in the future.
That's rare. At least it is in my experience.
A much better strategy than 'be yourself' is 'try to understand why other people think you are wrong'. That is a strategy that can improve over time. 'Be yourself' literally locks in whatever mistakes a person is already making.
Not going to judge anyone who goes with 'be yourself' but let the record show it is a bad way to approach life unless a body is very lucky in who their self is.
Jerks don't have a problem being jerks in my experience...
It is advice. There is a real risk that advice is going to be taken litearlly
If "be yourself" is a metaphor of some sort that means "assess if your personality needs change and then change it if you are a jerk" then that needs to be what people say in the first place. And realistically even then 'jerk' is too abstract. This is advice that requires psychic powers to interpret and as such is bad advice.
Don't pretend to know more than you do, be nicer, kinder, funnier, more generous etc. than you are...
I thought "be yourself" was a little more universally understood. It's very good advice.
Stop pretending so that you can accept where you are, deal with it and improve for the better.
For example, if you feel deep inside that you want to be an athlete, well that's a part of who you are, even if you're obese. You can embrace that by working toward becoming an athlete. Start living like an athlete in ways that you can.
In corporate situations this is a lot less ambiguous, where if you want to be promoted then you have to do the work of at least 1 rank above yourself before you're officially at that level.
If you feel like you're pretending and it's exhausting, then it either means you're not being true to yourself (you're not meant to become that) or you're suffering from imposter syndrome.
"Be yourself. But always be your better self."
People are complex, with many facets. Sometimes they act one way, sometimes they act another, and both of those can be true to the good, flawed, and inconsistent being that we are. We have better sides, and they are just as a part of ourselves as our flawed sides.