Digital communication

I just caught myself hissing like an angry cat at the screen. Somebody sent me some crap that I really don't want to deal with, and in response I hissed.

And then started thinking. I often do things like this, I give the screen the finger when somebody says something that deserves that respons, I curse at the screen, I laugh, I smile, I aaawwww out loud when somebody says or does something increadibly nice or sweet (So I'm not all bad and evil, ok?) The person on the other side neither hears nor sees this, and the cats don't care, so why do I do it?

I'm only half way through this thought, so I have no theory to offer yet. I wonder if others do the same?