Paint the room heuristic

The other day, my wife asked me if I could finish painting the bedroom before my conference call in 90 minutes. Naturally, I said that I could and like a good husband, I immediately got started. It wasn't until my phone rang that I realized that I hadn't made it in time. Luckily enough, it was no problem to delay the call by 30 minutes.

While I was finishing up, I realized what had happened. When my wife asked me if I could accomplish the painting in a certain amount of time, my thought process was...

1. If I do it now, it will make her happy.
2. If it takes a little too long, the worst that will happen is that she'll be a little grumpy until I finish, but once I'm done she'll be happy.
3. Once I start, no one is actually going to make me stop before I'm finished... I mean, who wants a mostly painted room?!?
4. I completely overlooked the fact that delaying the phone call could be problematic.