Note: I wrote this outside the context of this community, but I think it's relevant enough to crosspost here.
Some of the first questions many therapists ask a client are those meant to assess their friendships and other close relationships. This is because having a supportive community is one of the biggest strengths in those facing mental health problems. Whether it's Generalized Anxiety Disorder or grief over a breakup, having people you can lean on for emotional support can help a lot.
Women are more likely to have such social supports than men. Part of this is due to traditional gender roles and expectations. Emotional vulnerability is considered feminine, and thus more acceptable for women than men. Of course, anger is an exception here, given that it is linked with violence, which is linked with masculinity. So men are more likely to come in with anger issues, while women are more likely to come in with anxiety and depression.
The second part of this phenomenon is the difference between male and female friendships. Because emotional vulnerability is acceptable in women, it becomes an important part of the way women connect with each other. You can see this in media directed at teen girls: they support each other at best and tear each other down at worst, but it's all based in their ability to be vulnerable with each other. The trope of the girl giving her friend a makeover isn't just about looks; it's about self-esteem. The image of a group of friends watching a sappy romance movie and eating ice cream after one of them was dumped isn't just about being there for the friend; it's about empathizing and validating her emotions.
So what happens when you remove the emotional vulnerability from a close friendship? You get something close to what male friendships look like: a connection based in mutual interests, activities, and practicality. While it's not uncommon for two women with very little in common to become friends, this is far more rare with men. A guy's best friend may be someone they go to the gym with, someone they sit next to at work, or someone who reads the same books they do. A girl's best friend is likely to be someone who knows her more deeply than anyone else.
Of course, this is not to say women don't have shallow friendships and men don't have deep ones. Even media sometimes portrays men with emotionally deep relationships. Usually, however, this is referred to as a "bromance" and is played for laughs. It's not often these kinds of relationships are shown between multiple men, much less being shown as the norm. When it does show up, it's far more likely to happen between brothers, work partners (ie co-detectives), or best friends. Further, this model is based on Western gender norms, and thus might not apply to everyone in the same way. Some cultures reinforce emotional support more or less, and in different ways. Western gender norms don't account for other gender identities either. Those who are nonbinary or from other cultures might find that this applies differently, or not at all. Still, this is a useful frame to apply to others, especially in noticing different expectations for a close friendship or romantic relationship.
Speaking of romantic relationships, this often ends up being where men get most of their emotional support from. This is especially true in a heterosexual relationship, where the woman sees emotional support as part of any close relationship, not necessarily something specific to romantic situations. In a sense, a man is more likely to put all his eggs in one basket. His girlfriend can get her emotional needs met elsewhere if need be, but to him, she is likely the only person he can talk to about his troubles. This is why, statistically, the end of a long-term relationship affects men more harshly than women. If your emotional support comes only from within a romantic relationship, being single means you don't get any support. Worse still, men who struggle in their dating life have little to no support around this struggle, which in turn makes it harder to date. It becomes a downward spiral.
What about friendships between men and women? Well, this is where things get complicated. The old adage "Men and women can't be friends" probably comes from these different perspectives in what a friendship consists of. This is also why a woman whose friendship with a man is high in shared interests and low in emotional intimacy might be seen as "one of the guys". Since men usually only get emotional intimacy from romantic relationships, they think of this kind of closeness as a hint that the woman is interested in them romantically. This link is so ingrained that some men may associate emotionally close male bonds with gay relationships -- note the root "romance" in the phrase "bromance", and how often media makes fun of close male friends by calling them gay).
This is where the idea of the Friend Zone comes into play; this phrase has come to exemplify the difference between male and female relationships. A guy who feels he has been put in the friend zone by a girl probably saw the potential for a romantic relationship due to their emotional connection -- something that is rarer for him than for her. However, the girl may feel like she was seeking a perfectly normal friendship with a guy, only to be surprised that he was seeking a romantic relationship with her! In both cases, expectations didn't match up, and this can lead to the end of the relationship. The guy doesn't understand why the girl would provide and ask for emotional support while wanting to just be friends, and the girl doesn't understand why the guy would assume she was romantically interested when all she was doing was being a good friend.
It is important to note that while traditional gender roles can sometimes feel like they doom us to a certain kind of life, the world is shifting rapidly. On any middle or high school campus you can often find a few guys who prefer to make friends with girls, and vice versa -- often because of the ways they prefer to have friendships. More and more, people are picking and choosing what parts of their expected role they want to hold on to, if any. A particularly introverted woman may not want to have friendships that are about anything but shared interests, and this is okay as long as she finds other ways to regulate and process her feelings. Someone else may have a best friend they rely on for emotional support, and many other friendships based on a shared hobby. Finding something that works for you matters more than doing what other people decide is the right way to be healthy.
I want to encourage you to examine how traditional gender roles affect the way you build your friendships. Even if you don't identify as a man or a woman, the existence of these roles and friends who do or don't ascribe to them can have an impact. Someone raised a woman may feel they are expected to do emotional work for all their friends because this is what it means to be a good friend. Their friend may have been raised to see male roles as being preferable, and thus not want to be emotionally close with or show weakness to any of her friends. There are many ways people can respond to expectations, and even the "emotional closeness vs interest focused" dichotomy is overly simplistic and contains many other dynamics within it. But having emotionally close relationships (even just one or two!) is a protective factor for those with lots of life stress. If you find yourself bottling up strong emotions, needing to talk to someone but not feeling like you can reach out, consider opening up to someone a little. It doesn't need to go deep fast -- you can start with how much you hate being stuck in traffic or that you're upset you have to work on a Friday night. And if they respond in a way that feels good? Then, this might be the start of a beautiful friendship.