I have 3 games opened at the moment. Mario just threw a fireball towards hole 16 in the corner pocket, and you want me to chat with you?
I'm playing FIFA, it's the 89th minute, the 59th second, I'm in the lead by 50 goals. Maybe I'll concede a goal and lose. So DND!
I'm bored of playing on the computer, so I'm watching a movie. When I'll get bored of the movie I'll be back to the computer!
Now I have some stuff to do... Later I'll be busy; afterwards I'm going out. When I come back I won't have any time for you!
If I don't reply, I'm either way from the computer or I'm not in the mood to talk to you... But I'll surely be at the computer!