I usually don't get emotional, but when I see a father holding his little 3 yr old covered in a talis, on the way to the upsherin, I almost always burst into tears. The reason for the talis, is to protect him from the mazikim who will attempt to harm him on the way.
This innocent little kid, who at this point realizes nothing above the level of the candy he will be getting soon, is about to be traveling through a life full of such danger, that even the toughest person would shudder at the thought.
And with what protection from all those who are already seeking to literally kill him?
It's a cry of tefillah, that whoever this child should grow up to be, H-shem should watch over him throughout his life.