Well, just for a little bit. You don’t want to over stretch yourself now do you? Go for half an hour and you’ll feel much better for it. Get motivated, enjoy it, work up a sweat, then go and have some well deserved fun and chill time.
No way! Why the hell would you? You don’t feel like exercising so you don’t have to. Go when you feel like it, and if you never feel like it, so what. There’s much better things to do!