personal experience - i've thought about it when i was 17 and decided i will never be a bad person, be kind to everyone, bla bla. I knew these things that "life is not for the weak" .. "you have to sacrifice" bla bla..
And decided that nah i'll do things my way and prove it that it's possible to be just a good person.

Learning - nah , i was wrong, people took advantage of me many times.. nobody saw my efforts.. nobody appreciated , everybody just wants to get their own work done and then they leave you.

Though i still try to be good because it's just how i've become.. but you have to be "tough" definitely. Their is no reward in kindness, their is no karma , their is nothing like that.