Who disappears? I would like to learn that trick :)

Sorry. Looks like there's a bug with this app :-/

I think sometimes they are just busy with other things happening in life. Some people take very serious their etiquette online, while others do not. I don't think anyone does it with the intent to make you feel bad.

some just leave without saying anything and didn't give you any preparations. It's really hurting.

I think everything is always a reason and some people may be busy with different thing which you don't understand.