“Why” is one of the more essential question to have in mind whatever you do. I am not trying to get all philosophical, but keeping “why” in your mind is pretty important.
Do not ask people “Why” all the time because that gets really annoying after a couple of “why”s, so it is best to find out “why”s on your own with a bit of thinking.
By trying to figure out one “why”, you are able to find answers to many other “why”s and that can help you improve whatever you are doing drastically and rapidly.