I should be thankful

Yesterday on my way home I was happy to have a little more time to deal with housework than usual. While thinking at my home chores to fulfill before the following 3 days of holiday, some noise distracted me. There were a woman and her boy walking in front of me. The woman was dragging a heavy shopping trolley with one hand and holding the boy by its shoulder with the other. The boy, 7-9 years old, was hitting the pavement with a stick from time to time, quite disturbing in those quiet streets. As I got closer I've noticed it was not a stick but a cane for a blind person. I felt guilty then to think for only a moment that the noise was irritating. I felt anger at the idea that there is child that is blind and has to deal with learning how to use a cane just to survive walking by the street and that his entire life will be a struggle. I saw his little face: he was smiling while talking to his mom. Why him?
And than I felt that I wasn't thankful enough for what I am, for what I have: I can see, hear, talk and walk. I'm a healthy person that can still eat whatever ones want, that knew what love is, that has a loving family, friends and a roof above its head. I always forget about those things when I'm upset, when I ask for more, when I don't like something. I should consider myself a lucky person for what I've been given.
Thank you!