See that you do not despise one of these little ones; for I tell you that in heaven their angels always behold the face of my Father who is in heaven.( Mt. 18:10)
Today we celebrate "their angels" and our angels, the guardian angels.
Perhaps the answer to why we don't think more about them is that we do think we need a guardian. A guardian is usually defined as a person who looks after and is legally responsible for someone who is unable to manage their own affairs, especially an incompetent or disabled person.
Which of us wants to admit that we cannot manage our own affairs? The truth is, we can't. Left to our own devices, we fall down every time. On our own we cannot get through a single day without doing or saying something that we know is contrary to the person God has created us to be.
Guardian angels are simply one more of the many ways that God offers us assistance. Today let us put away our hubris and admit that we need all the help we can get.
We are all "little ones" in the great scheme of things. Perhaps you haven't thought of your guardian angel in years. Perhaps you have never thought of your guardian angel. Clearly, Matthew's gospel tells us they exist. Perhaps today is the day to say Thank You. And since all angels are messengers, perhaps today is the day to listen for the message, to listen to the message.