Daydreaming is important business:
Every time we slip effortlessly into a daydream, a distinct pattern of brain areas is activated, which is known as the default network. Studies show that this network is most engaged when people are performing tasks that require little conscious attention, such as routine driving on the highway or reading a tedious text. Although such mental trances are often seen as a sign of lethargy -- we are staring haplessly into space -- the cortex is actually very active during this default state, as numerous brain regions interact. Instead of responding to the outside world, the brain starts to contemplate its internal landscape. This is when new and creative connections are made between seemingly unrelated ideas.