How bad is a RE-4 discharge from the navy?

It was bad.If you want to join any branch again, you will never be allowed to, and you could lose your VA benefits as well as federal or government jobs.

A RE-4 code is usually given because of drugs, a pattern of behavior or a serious offense.If the condition is irreversible, it can be given.

You can't re-enlist in the armed forces again.The civilian side just looks at the general classification of the discharge.

Unless it's an entry level separation in basic training for failure to adapt, it usually means they have a pattern of wrongdoing.The character of service needs to be looked at.Other than honorable or bad conduct.

It means that you aren't good enough for the Navy because you're fed up.You made a mistake.

Staying out of trouble is what you have to do in the military.It's that simple.