Youcat commented through CCC – Question n. 318.

YOUCAT Question n. 318 - What are vices?

(Youcat answer) Vices are negative habits that deaden and dull the conscience, incline a person to evil, and habitually prepare him for sin.    

A deepening through CCC

(CCC 1865) Sin creates a proclivity to sin; it engenders vice by repetition of the same acts. This results in perverse inclinations which cloud conscience and corrupt the concrete judgment of good and evil. Thus sin tends to reproduce itself and reinforce itself, but it cannot destroy the moral sense at its root. 1865 

    Reflecting and meditating 

(Youcat comment) Human vices are found in connection with the capital sins of pride, avarice, envy, anger, lust, gluttony, and sloth (or acedia, spiritual boredom). 

(CCC Comment)

(CCC 1867) The catechetical tradition also recalls that there are "sins that cry to heaven": the blood of Abel  (Cf. Gen 4:10), the sin of the Sodomites (Cf. Gen 18:20; 19:13), the cry of the people oppressed in Egypt (Cf. Ex 3:7-10), the cry of the foreigner, the widow, and the orphan (Cf. Ex 20:20-22), injustice to the wage earner (Cf. Deut 24:14-15; Jas 5:4).

(The next question is: Are we responsible for the sins of other people?)