A few points from a Pyromaniacs post about the nature of sin and sinners:
Sin only makes sense to itself (cf. Genesis 3), and to other apostates (Proverbs 28:4a). Sin makes you irrational, insane, crazy, nuts (cf. Genesis 3—Revelation 22; especially, for instance, Genesis 3:8; Numbers 13-14; Matthew 12:24; Ephesians 4:17-19). People locked into a sin are impervious to logic, facts and Scripture (cf. Genesis 3:9-10). People locked into a sin always say it’s someone else’s fault (cf. Genesis 3:12-13). People locked into a sin hate anyone who tries to tell them the truth, no matter how humbly nor lovingly (cf. 1 Kings 22:8; John 3:19-21; Proverbs 15:12). People in love with a sin will always find dire and horrendous fault with anyone who tries to part them from it (cf. Proverbs 9:7-8a). Sin destroys, ruins, kills. Its sales-line is a lie: it has nothing we really want (cp. Genesis 3:5 and 7; Romans 6:23). Sin doesn’t care who it hurts, nor how much, nor how devastatingly, as long as it gets its way (cf. Matthew 10:34-36). There is no sin — no sin — that can’t make an excuse for itself that makes sense to itself (cf. John 11:50; Philippians 3:19 [“they glory in their shame”]). Every unrepentant sinner sees himself as noble (cf. John 16:2). Every unrepentant sinner sees his sin as different (cf. Romans 2:3-5). Everything a sinner does to “fix” his situation apart from repentance only serves to make it much, much worse (cf. the sad story of Saul) You can’t talk anyone out of sin (cf. 2 Timothy 2:24-26). The only and sovereign cure for sin, still, is the blood of Christ, applied through humbled repentance (cf. Matthew 3:8; Luke 5:32; 15:7; 24:47; Acts 11:18; 17:31; 20:21; 26:20). There is no “therapy” for sin (cf. 1 John 1:8-10).