Avos 3:10

Rabbi Chanina ben Dosa used to say that one who finds pleasure in the eyes of mankind also finds pleasure in the eyes of God but one who displeases mankind also displeases God. Rabbi Dosa ben Harkinas said that morning sleep, midday wine, childish talk and sitting in gatherings of ignorant people all drive a person from this world.

Avos 3:11

Rabbi Elazar of Modin said that if a person profanes sacred things, treats chol hamoed lightly, shames another person publicly, ignores the covenant of our forefather Avraham (i.e., circumcision) and interprets the Torah not in accordance with halacha, even if he possesses Torah knowledge and good deeds, he has no share in the Next World.