The problem with time is that we always seem to think we have enough.

I'm not studying for the SAT right now because I think I'll have enough time to study for it later. 
I woke up five minutes later this morning because I thought five minutes wouldn't be much of a difference. It was, by the way.
I was supposed to clean my room before my mom got home from work. I thought I would get it done before she got home, but I didn't. 
I didn't spend time with the people I wanted to because I thought I would have tons of time with them. 

Overestimating the time you have is easy.

You think you have all the time in the world, but then you realize you didn't have all the time you thought you did when it runs out. At that point it's too late to do anything about it. 

Sucks to suck.