Whether the persona they show is more or less like their true self depends on what you consider their "true self" to be. If you look at any sort of school of thought which embraced asceticism, you'll find people that, because we experience way more emotional changes over a day than we experience changes on our set of desired behaviors, came to think of emotions as unreal, annoying distractions. The major example of this kind of thinking being Stoicism, but really, it just of sort of permeated every other pre-modern society.

So yeah, I don't think it's a "puritan/evangelical" thing. It's more of a "anything but contemporary urban society" thing.

I think it can also be situational as well - you can obviously be freer with emotions with close friends then at work.

(46, English)

You wouldn't want to live in a society where everything acted on their emotions only.

Yes, I actually want to live in a society where people are a lot more open when it comes to expressing their emotions and feelings compared to a society which actively tries to supress them and instead rely on other social tools.

That's actually one of the few reasons why I've still not emigrated yet. The few countries which I now find economically stable are generally seen as "cold" when it comes to human interactions and expressing your feelings (Norway, Germany, Netherlands, Sweden) while the few other options which I found a lot more similar to my country (I now live in Romania) have been going through difficult economic times lately (Spain, Italy).

You are missing the point.

If people acted on their emotion (i.e. mostly controlled by our reptile brain) it would be a very violent society and quite frankly unsustainable.