how do we keep our decency?

I wonder, how do good, honest sincere people keep being like that in this world, this world that is full of filth, corruption, distraction, etc. with social, financial and many other systems that encourage evil, manipulative behaviour. We can say we try our best but how long before we crumble because we have been forced into a position that we have to compromise our beliefs and decency..and do that repeatedly, if not we won't be able to get ahead or survive in this world. So the cycle of evil and cheating continues and we continue to harm people and compromise and say, 'well, I had no choice' and eventually we numb our conscience towards it, and the decent among us becomes less and less...So how do we keep our decency?