That ye put off concerning the former conversation the old man, which is corrupt according to the deceitful lusts; (Eph 4:22 KJV)
LUSTS? No. Scratch that. It's "epithumia" which is really just the word for desire like some of the newer translations have it:
Regarding your former way of life, you were taught to strip off your old man, which is being ruined by its deceptive desires, (Eph 4:22 ISV)
Action proceeds from desire. After all, if you were perfectly content, desiring nothing, you wouldn't do anything at all. What would be the point?
Can you imagine it? If every desire you had was good then you could literally do whatever you desired. The fact that people do things that are bad shows that people have some desires that are not good. You can argue endlessly about what is good and what is bad, but (unless you are a nihilist) you gotta be honest and admit everybody has some bad desires in them.
That's the real problem. However you want to define "bad" - bad desire leads to bad action and bad action leads to ruin.
OK then! Let's all get rid of our bad desires and make a perfect world. We just need to desire to desire some different desires.
Changing desires requires more than knowledge of what desires you ought to have and more than will power to desire something different. The stronger the will power gets, the better the will power is at acting out on its desires. Unfortunately, those desires may very well be the wrong desires to begin with. You can just as easily wind up using that stronger will power to act on the deceptive desires.
It won't work. If that's all it takes mankind would have become perfect centuries ago.
Shoot. Something is missing.
Unless and until a way is found to deal with those deceptive desires, just telling people to be good isn't going to get you very far.