Critical Thinking, which is something you might not have developed yet. Lack of stimuli that challenges your own perceptions, literally being closed minded/not thinking by yourself.
What do you mean by that? Guessing from previous discussions: Taking anything online (that maybe/remotely resembles negative feedback) as a serious (and important) critique?
Start listing facts in your mind and deduct yourself if every statement online should be taken as serious/important.
* Text doesn't transfer feelings, facial expression, gestures
* People are lazy and type short (especially on phones)
* Many don't think of possible misunderstandings and don't give a sh*t on how the recipient takes their statements
* Malice exists and the (pseudo- or perceived) anonymity online amplifies bad traits