Why do i do this?

Hi dano218, I think your problem is normal to feel more expressive online than in person. I do the same thing and it is annoying especialley if you want to speak to maybe a crush or something and you can't show emotion. I think you just need practise maybe like expressing an opinion or something. I also think it's normal to not reveal feelings to friends aswell so don't worry over that.

 

Same here. I just found out yesterday what is MBTI, and I took the test too. According to that I'm INTJ, and it's description says almost exactly what I observed in myself. Regarding emotions, it says:

"INTJs are defined by their confidence, logic, and exceptional decision-making, but all of this hides a turbulent underbelly - their emotions. The very notion of emotional expression is synonymous with irrationality and weakness to many INTJs, a display of poor self-governance and fleeting opinion that can hardly stand up to the enduring light of factual truth.
This mistrust of emotions is understandable, as Feeling (F) is the most weakly developed trait for INTJs - like any complex tool, skilled hands can use it to remarkable effect, while untrained hands make clumsy and dangerous work.
People with the INTJ personality type take pride in remaining rational and logical at all times, considering honesty and straightforward information to be paramount to euphemisms and platitudes in almost all circumstances. In many ways though, these qualities of coolness and detachment aren't the weapons of truth that they appear to be, but are instead shields designed to protect the inner emotions that INTJs feel. In fact, because their emotions are such an underdeveloped tool, INTJs often feel them more strongly than many overtly emotional types because they simply haven't learned how to control them effectively."

Source: INTJ Personality

Like you, I'm also more open online, because there is a distance between me and the recipient, so it feels "safer".

Finally this recent discovery highlighted something that I may have misinterpreted in my self-analysis. Until yesterday I was convinced that I'm totally emotional, but some hang-ups prevent me from expressing what I feel. But I reevaluated things, and I'm not so sure now.
Basically anytime when I was in a situation when someone close to me was crying or upset, I tried to help him/her by trying to come up with rational solutions. And most of the time my only emotions were discomfort and anxiety. Whenever someone is crying or sad or anything like that in my presence, I feel like running the fuck away. I keep thinking "Just stop it already, don't do it!".
For example whenever anybody in my family mentions my mother who died one day short of a year ago after more than a year of excruciating pain and agony, I scream in my head: "FUCK YOU, STOP THIS SHIT, I DON'T WANT TO HEAR IT, SHUT UP, SHUT UP, SHUT UUUUUUPP!!!", and I try to think of something else, anything else.
Maybe it's some kind of PTSD, but I'm like this with many thing where emotions are in question. Showing emotions beside anger, hate and happiness (though moderately) are not my thing, but when I'm alone, I can feel really deeply. But not expressing them. I can't even cry when alone. Maybe I'm afraid of feeling? The fuck knows...

Sorry for the long rant, check out the site I mentioned, maybe it will help you in some way.

 

It's really not unusual. When you are writing about your feelings you have time to pause, consider, reflect and edit and it can help you to articulate things much better. In a face to face conversation you normally have to offer an immediate response and you may also be presented with certain barriers, like personality, body language and tone of voice. You may also be challenged or interrupted and end up feeling more frustrated that you were unable to make your point.

The written word is better for some people.

 

I'm in the same boat as you on this, mostly because of the anonymity online forums have, I'm happy to share personal details about me as there are still 1000s who could be me. I just physically can't talk about emotions I just hate how vulnerable I feel when I'm upset. I've almost gotten too good at bottling things up.