Many people know what they ought to do, but do the opposite anyway...according to James 4:17, What do you think?

Let's look at James 4:16-

Otherwise you are boasting about your own pretentious plans, and all such boasting is evil.

James 4:16 NLT

We are to only boast about what the Lord has done, not what we have done. Let's look at 15: 

What you ought to say is, “If the Lord wants us to, we will live and do this or that.”

James 4:15 NLT

Everything we do should be for the glory of God, and the glory of God only.