How often have you gotten coffee with a friend, but have been simultaneously planning how you're going to get homework done or what you're going to do between getting coffee and work? We all experience things like that every day. When you're with someone talking, but you're thinking about something else, you're really just talking to yourself. Don't spend all your time planning what's going on in the future, or you'll miss what's going on now.
Be in the present, be here, not there.