Should my happiness be dependent on the suffering of others? Once I asked a wise man "Why should I be happy?" He said "Because there are people more miserable than you. Thank God that at least you are better than them."
There are couple of depressed kids living in my neighborhood(people call them mad). Sometimes I feel happy that at least I am not depressed or mad. I use their depression as a reason for my happiness.

My question is (from the Buddhist point of view): Should my happiness be dependent upon the suffering of others? In other words should my happiness be dependent upon my ability to find an example of new low in the human suffering?
For the question, "Why should I be happy?", if the answer is, "Because there are people more miserable than you. Thank God that at least you are better than them," I think this is not an answer appropriate for Buddhism. 

The reason is that today there are other people worse off than you, but in the future, it is also possible that you are worse off than them. That's anicca - nothing is permanent. This answer also shows a lack of compassion and loving-kindness.

Instead, you can generate happiness through the Brahmavihara of loving-kindness (metta), to wish that both you and them would be happy, safe and at ease.

The other Brahmavihara is compassion (karuna). If you can't alleviate the sufferings of others, at the very least, you can contribute towards not increasing their suffering.

From the Karaniya Metta Sutta:


  Think: Happy, at rest,
  may all beings be happy at heart.
  Whatever beings there may be,
  weak or strong, without exception,
  long, large, middling, short,
  subtle, blatant, seen &amp; unseen,
  near &amp; far, born &amp; seeking birth:
  May all beings be happy at heart.
  
  Let no one deceive another
  or despise anyone anywhere,
  or through anger or irritation
  wish for another to suffer.
  
  As a mother would risk her life
  to protect her child, her only child,
  even so should one cultivate a limitless heart
  with regard to all beings.
  
  With good will for the entire cosmos,
  cultivate a limitless heart:
  Above, below, &amp; all around, unobstructed,
  without enmity or hate.
  Whether standing, walking,
  sitting, or lying down,
  as long as one is alert,
  one should be resolved on this mindfulness.
  This is called a sublime abiding
  here &amp; now.