Some people can continue talking so harshly - taking for granted someone who doesn't take things to heart. "No matter how I speak, this person will still treat me kindly anyway".
Some people can feel so envious of another's happiness they start comparing lives; "why does she have it and I don't?"
Some people cannot see another person so happy and content, they start making other people take sides. This I have seen a lot.
Some people look for a person only during down times and they forget friends when they are at their happiest.
Some people can be so calculative they expect something so much bigger because of one little kindness they may have given before.
Some people suddenly become your friend instantly when you are recognised for something good; "Oh, we grew up together" or some crazy ancient story like that.
Treat people with kindness, and never take for granted blessings (no matter how small) that are right before your eyes. It can a beautiful day (and people still whine when it's too hot or when it rains!), it can be a small surprise from someone, it can be a nice person, it can even be a smile from a stranger. All these little thing and kindness make all the difference. Cherish it and always count your blessings before you even ask for something, a little more.
I just feel very thankful for the handful of people I see every single day who are always positive and happy - they never fail to make me feel content. Happiness is a choice and it's really free! So don't waste em energy competing with your inner self :)