One of my favorite quotes is from Rav Yisrael Salanter. He said, "The loudest sound in the world, is the sound of a bad habit breaking!
The Rambam also speaks of the danger in doing even minor sins habitually. Unless a person does Teshuva, he also could lose his share of Olam Haba.
Some of these minor infractions done on a regular basis are: Calling a person by a nickname ( even if he doesn't mind,) embarrassing someone in public, getting honor at someone else's expense, treating one's rabbis and Torah scholars in a demeaning way, and not showing proper respect for Chol Hamoed, by treating more in a profane manner rather than in a holy manner.
The Rambam recommends some serious soul searching for habitual violators of these sins mentioned. We must not despair for there is always room for Teshuva.