why are some people weird on here

like i have a few users who will at times answer my posts with helpful thoughts and words and i get from them that they care, but then, those same users will answer me another time and post something which sounds' blunt' 'short' ' to the point' like they couldn't care less about my circumstances...so, what should i make of that?

to me that is a little weird.....and it's hard to trust people of give them any credibility when they behave like that.