I love HN...I've been waiting for this topic :-D
I'm a man who has focused on and has been building tools to get better at expressing my emotions since 2012, including an app called iFeelio, in which I answered the question "how do I feel" over 4,000 times across 4 years and a class called Emotional Self-Defense, which I've run in the US, Europe, and Africa. I have realized and re-realized many things along the way.
One thing I've seen is that each culture seems to have rules about which emotions one is allowed to express and not allowed to express, based on the specific contexts. We often say that men aren't allowed to express our emotions, but I don't think that's the case. We men (in the US) are often allowed to express anger, confidence, feelings of triumph, horniness (maybe), calmness, and maybe even excitement. We're often not allowed to express tenderness, sadness, confusion, uncertainty, fury, etc. And funny enough, when watching our favorite sports team, we're pretty much allowed to express all of the emotions above and more. On the other hand, in the workplace, we're not allowed to really express much at all.
Women may have a different list, as well as people from the Midwest or California, those born in the 60s, digital natives, engineers, or really any different culture or sub-culture.
That being said, I'm glad to see programs like MKP and Evryman providing the place, and moreover, the permission, to express all of the emotions. (Save a Warrior is one I recommend for military vets—I was a witness on one of the programs and it really helped to open my heart and the hearts of the other guys.)
I'd love to chat with anyone on here about this, either in the comments or on Twitter, Telegram, keybase, or whatever people on HN use these days. Check my HN profile for those usernames.