In other words, I am urging you to remain a good person regardless of the bad eggs around you.
It's impossible to make no contact with bad people. In this world where the good, the bad, and the ugly cohabit. No amount of protection can exclude us from being directly hurt by bad people or seeing them hurt others. It could be at home, work, school, or in your place of worship. They could harm you so much that you question the use of being different. Their action can push you to change for the worse as you seem to see no good emanating from maintaining a fine attitude and disposition.
Why you should maintain a positive attitude
"An eye for an eye will leave everyone blind" – Mohandas Gandhi
If we all repaid evil for evil, just what good will be left? Two wrongs, they say, never make a right. As such, repaying good for evil is most certainly the right thing to do. Who knows, your fine conduct could make an evildoer make changes. It can soften and refine him the way a furnace refines glassware. There's no need to grow hate.
A positive influence for others
If everyone were to become bad as a result of the bad done to them, what will the coming generation learn? True, not everyone can be classified as good, but we don't have to spread the hate. If you never stop being a good person, you will be a breath of fresh air amidst the pungent odor of badness. You will be a positive influence on others, a good example and reference point for those who strive to continue doing good despite injustice.
One good turn deserves another
Just like the law of Karma, what goes around comes around. The good you do will find its way back to you. In a place and time when you need help the most but are unlikely to get it, you might be amazed at how you'll be repaid for your kind disposition towards life and others.
Imagine this scenario, you walk down a particular route daily and often see the same faces but no one ever says a greeting to the other. You decide to be the exception. Each day you make sure to wish whomever you see a good morning and a bright day ahead. Trust me, the day you don't go down that route, you'll be missed. The next time you do, they'll definitely mention that they didn't see you pass the day before. See how much care a simple greeting can get you.
It is true that being exposed to negativities over a long period of time can breed a bitter and sour attitude. But it's possible to keep a positive attitude by doing the following:
Look out for the good in others.
Make excuses for their actions.
Trust that each one will be rewarded according to their deeds.
Recognize that vengeance isn't yours to take.
Meditate on how your good attitude benefits others.
Know that being at peace is better than being right.