Anger.
Do you think that it's wrong to be angry?  Do you believe that anger is a sin?  Many people do.  God doesn't.

Be ye angry, and sin not: let not
the sun go down upon your wrath:
- Ephesians 4:26

If anger were a sin, then we couldn't "be
angry and sin not".  Anger is not a sin.

whosoever is angry with his brother without
a cause shall be in danger of the judgment:
- Matthew 5:22

Being angry without a cause is wrong, but that
doesn't mean that all anger is wrong.  That would be
twisting God's word to serve some other purpose.