I will admit to a character trait that can be both positive and negative in its consequences. I am prone to becoming almost totally consumed with something that I sink my teeth into. When this happens, I can tune out most other things and concentrate intensely. Let me give some examples.
At college I was working on a major computer lab project (designing and constructing an electronic calculator from discrete digital parts). I was so engaged that sleeping and eating became a nuisance and I worked all day and all through the night on it. I don't recall that there was a particular deadline driving the behavior. I was just consumed by it.
At college (and since) I tend to perform better when the heat is on and I immerse myself totally in an assignment (working like a madman the day and night before something is due, rather than sanely over multiple days).
I can be mulling something over in my head and become largely oblivious to conversations or events around me. This can come across as rude when I seemingly ignore or am unresponsive to those around me.
When I planted our grass lawns at our new house in Idaho I was obsessed with them. That's all I wanted to talk about at the dinner table. Each day I would observe how the grass blades were growing, how to water it, what the weeds were doing, etc.
I love troubleshooting problems. This has been a great plus in my engineering career, as various product development efforts have had significant bug finding and fixing activity. When I'm hot on the trail of troubleshooting it is hard to break free and go home to dinner. This has yielded significant job satisfaction for me, as well as contributions (and rewards).
Last week I did a bunch of research and decided to upgrade our computers at home to Windows 7. Once again, it was heads down doing research, installation, and troubleshooting, and all other life activities became a nuisance.
I think a downside is that I don't multitask very well. When multiple things enter my brain I tend to latch onto one and drive it hard.
I'm sure I'm not unique with these qualities. I see them in my father, and I'm sure I have passed them onto my children to some degree. I suspect males are more apt to be this way than females (Suzanne reminds me often she can't afford this behavior when there are kids around to watch over).