Why is it easier for me to work on multipolar tasks at one time then it is to just do one?

Multitasking. This is generally just a cognitive preference that varies from person to person. Generally it reflects easy boredom and difficutly concentrating on a single task in a sustained way. For minor tasks, this works fine. For important, creative work multitasking is a less effcient style. See the discussion in john medina's book "brain rules.".