Why guys become casual with me? They do not maintain good guy facade?

Guys become really informal with me, they would share their inner thoughts with first few meetings. They would share their personal life problems, their inner thoughts with me. For example this guy was unavailable for a meeting, without me asking him he would say to me that he was dealing personal life Problems whereas same guy would say to other colleague that he was sick that's why he was unavailable. Why this guy become comfortable sharing their inner thoughts to me like he personal experiences without me making any effort to be friendly towards him. Why do not they maintain formal good guy image like he was doing with other girl colleague. Is there something wrong with me. In the past this happend with me a lot, new acquinted guy would overshare with me about his life on the first meetings
Why guys become casual with me? They do not maintain good guy facade?
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