When an E-4 calls me "hey" or "hey man" knowing that I am an officer, should I bother to correct him?

Light his or her behind up. You have earned your rank correct? You should be addressed as the proper rank. Buddy or not. He or she needs to know when we are in uniform you WILL address me as Sir or Ma'am. When we are on our personal time or in civian clothes away from our uniform its a different ballgame then. I know for me I have had plenty of officers that retired and still to this day I address them as Sir or Ma'am. Even when they say I am not in anymore no need for that. For me its a respect factor. Have that person write you an essay on why it's important to address your peers or others by proper rank.

The short answer respect, customs and courtesies doesn't end at the end of the day.

If they respected you as they should, this wouldn't even be a discussion!

If you accept that behavior you just lowered the standard. Do you want to be that person who contributes to further lowering the standards in the military? Seems to me far too many people have done that to our military already.

The Soldier said this 'Outside work' It is not a requirement to call you sir while outside of uniform. Yes, it is a polite thing to do but not required. There is nothing wrong with him talking to you like a human and not like a robot.

If your the same age as said SPC, yeah hey man is aight

Regardless, on or off-duty, of enlisted proper addressing to an officer before and after each sentence is with Sir or the rank Captain. This is in accordance with TC 3-21.5 "Drill and Ceremonies." Even privates if they are unaware they need to be corrected on the spot, if not by you, then by an NCO as I did. Remember you're running for a popularity contest but a commissioned command as a "Captain."

You should always, regardless of rank should be corrected, this is because the proper military standards and regulation TC 3-21.5 is to instil proper military bearing and behaviour on all soldiers from the enlisted to senior officers just alike. Furthermore, one thing is to care for your soldiers another thing is to become buddies with them. Such behaviour from an officer can be reprimended.

Saddened that you have to ask the internet this question. Sqash it! I would not have allowed that when I was Sergeant, let alone an officer. The fact that they even try to do this speaks volumes about their training and discipline or the lack there of. Before you grill them check yourself. Are you putting out the vibe that this is OK? What kind of social setting are you sharing with them? Maybe you need a change of scenery.

I hope you do, afterwards have him do 50 pushups, and have him apologize, made next time he'll remember how to address an officer

Is this really a question? Absolutely light them up. Standards and professionalism, customs, courtesy, respect. If you don’t correct mistakes you endorse them and our professional culture suffers from weak knee leaders who let it slide.