When I was a kid, one of my biggest wishes was to become wise as I get older. Looking back, I enthusiastically worked towards that by studying and learning about many subjects (cultures, politics, arts and sciences, among others) on a generic level just to have a more clear big picture. At times, the increasing understanding pushed me through serious struggles, especially at moments when I realized that something that I had long thought was true, wasn't.

The quest for truth and wisdom will probably always be painful. The more you work towards it, the more you find how nearly all "truths" are somewhat relative and subjective, and choke-full with biases. However, there are also moments where the realization of truth leads to comfort, balance, and even happiness.

One of the best things to happen with increased wisdom is to become a mature person. Maturity is a major source of happiness. Years back, when I read statistics about older people being generally happier than young, I wondered how that could be possible. The studies said it being a result of older people being more comfortable and in better balance with themselves. I wholeheartedly agree.

The following quote by Robert M. Price has been influential on me(all emphasis are mine):

It is simply maturity to reach the point where you are no longer insecure and can rejoice the success of others. When you don't have to make others look bad for you to look good. The mature person is not defensive and readily yields when his opinion is refuted, because he just wants the truth to emerge, and it doesn't matter from whom. The mature person ... knows that her own interests include those of others and do not compete with them. The mature person automatically seeks out to put others at ease, feels no need to dominate conversations, and patiently views detractors as merely childish until and unless he is forced to conclude that they are evil. 

The mature person hopes to be given the benefit of the doubt and knows he must give it to others, if only to avoid jumping the gun and being mistaken. The mature human being is humble yet rejoices in his strengths, no longer thinking to pat himself on the back for them. He does not fish for compliments or make sure everyone knows of his good deeds... He does not feel impelled to set others straight and correct their opinions, believing instead that others will learn gradually and at their own pace as he himself has done. When struck or insulted, the mature person is secure enough no to return wrath or harm (unless, out of self-defense, he must repel serious violence)... When criticized, the mature one will first ask himself if the complaint is true, and, instead of resenting it, he will take it to heart. If you are mature, you will shrug off offense and look for every opportunity for reconciliation... 

It is just a question of growing in wisdom as one grows older. One must be willing for it to happen, but it is not a miracle. Nor does sincere moral maturity ever think of deserving or receiving some reward for doing the right thing.