What one thing makes you humble?

I feel humble when I see love.  Sometimes its romantic love between two people.  Other times its the kind of love you see between a parent and a child.  Other times is love, not in the romantic sense, between people.  No matter how you look at it, it's love, and it's grand.  There's nothing going on around them that can stop what you see.  This picture shows exactly what I mean.

I am also humbled by people who are "sicker" than me, but have a much stronger mental attitude.  I watched a documentary on PBS tonight about people who were going through organ transplants.  It was meant to gain awareness of organ donation, but some of the people were so sick.  Yet, they were so strong and full of life.  I feel lifeless, but the reality is that I should be full of life.  Those people, are my inspiration.