I can be concentrated and focused for about 4 hours if not disturb by anything or anybody. In fact at times when the weather is also very nice and pleasant and there aren't a lot of people around so there is less noise, I can even go for six hours in a row without thinking of anything else apart from what I am doing.

If if I am disturbed, I easily lose concentration. And when that happens, at times it is really hard to gain it back. So at times when I am working on something and I am really focused, and somebody perturbs me I might never get to that point of focused anymore maybe except after a long while.

For that reason, I like to stay out of sight when I want to concentrate and work on something really important.