Can someone always be a good person?

From my own philosophy of life, every human is created good one only becomes bad after he or she has become corrupted.
Also by looking for the good side of person makes one to see good things in a person so therefore, to remain or to be a good a person in life, one has can write down the list of good attitudes in life and after each day the person ticks what he achieved for that day with time and carefulness one will remain good.