Sometimes people cannot change their attitude towards a certain environment or person or life in general due to self inflicted unwillingness to change, better known as pride. However, there is usually something that happens in their life that either forces or causes a change to take place, what does it take to humble you?
Gratitude. When I think about everything that I am, all that I have in my life, the health of myself and my loved ones, I am humbled to my knees. These gifts are amazing to me, and cause me to want to reach out beyond myself and give to others.
It really depends on what I'm being humbled about and who is doing the humbling. I try to be a humble person to begin with, and I certainly don't have any grand stature in life to be anything but humble. The only time I really feel my pride rising is if I am in a debate with somebody who is very aggresive in their opinion towards me.
Usually, my being humbled comes if they can prove me wrong in a very absolute manner. That's usually one of those dig my toe in the sand moments.
God humbles me all the time by showing me how much more I have in life than other people. Like Farseer said, gratitude is a huge humbling experience.
God has had to smack me in the face a couple times, though, by life altering experiences. One of those instances should have taken my life, but by the grace of God I'm still here. That certainly turned me around right then and there.
I am weird. My pride lies in the fact that I am humble. If I am wrong I will go to great lengths to correct it. But if I am right I will not gloat about it. I try not to be arrogant about it.
Generally, it's the unexpected acts of kindness by someone I've previously judged to be an idiot. I know that I have a nasty habit of judging folks before I've had a chance to get to know them -- but, in my defense for the most part I'm usually right with my first instincts. It's only when I've gone out of my way to show that I must be right that the person does something wonderful and I'm left with a dish of crow to munch on. I believe I'm learning in my old age to allow my pessimistic side a vacation day when meeting new people. (occasionally)
Seeing other people's needs and try to meet those needs, humbles me tremendously. I love to serve people and God humbles me in my many ways by showing me how many blessings I have in my life. It also takes lots of struggles and bad experiences to reach the stage I am right now...I am very far from being humble but I have improved quiet a bit. If we are really humble, then we would not acknowledged it openly, boast about it or even mention it. Humility is something deep inside of you that brings that sweet feeling to know you are doing the right thing without looking for recognition of any kind. Humility is to accept when you are wrong and even to say you are sorry even if it wasn't your fault.