Regardless of military branch, which pay grade is most challenging to deal with?

For me the hardest rank to deal with was 0-1, or better known as the "Butter Bar." We had a general that told all of our 0-1's if they were going to argue a point with any senior NCO, they had better be right, or those young officers would be on the carpet answering as to why they would challenge someone about their job that had more time in a latrine than they had in the army. I had a case with a young butter bar that Was pretty funny.
I was an LNO working in Corps HQ on a new targeting system. I was over seeing several Bragade HQ's during the exercise. One of the Bde LNO's was a butter bar, and I would see him in our shop all the time. I had to go to his units HQ to troubleshoot some equipment problems they were having, and was working closely with one of their captains. This butter bar comes in screaming at all the Senior NCO's in the TOC like he ran the place. As he was leaving the TOC to head back to my TOC, I looked over to the captain and said, "do you know why I like butter bars?", he answered "no." I said, "because they taste just like chicken." That LT turned bright red and started walking my way when the captain asked him if he had a problem. He said "No sir" and stormed out. He then went to my commanding general and explained what I had done. The general told him that I was a pretty damn good cook so he would take my word for it. Best general ever. Lol

Nice sign there Sarge! Bad run in with a warrant officer or something? LMBO, too funny actually and are you sure they used the word "hole"?

What ever grade I'm not is the simple answer!

I'm not sure, but I do know - FOR SURE - that it's not warrant officers, SFC Mark Merino!

Sorry LCpl's......I had to.

SPC.E-4, because they know enough to be dangerous, but it is hard to convince them that they still have crap to learn. Oh, sorry, Stuff to learn. They are like teenages, you need to give them something to be in charge of, while they still think they know everything. :-)

PO First Class being invited to dance (Making Board), not getting ask to dance (making Chief Select).

CSMs... hands down.

In my experience I would have to say easily the O1 rank. Being prior enlisted I knew better and actually listened to my NCOs to become educated, not only did I cross ranks I crossed branches. Going from Marine Corps enlisted infantry to Army transportation officer is a huge hurdle and I knew next to nothing about the Army. Thankfully I used my enlisted knowledge to know to shut up when needed and learn from my awesome NCOs. It has helped me become the officer i am now and couldn't have done it without them. In my BOLC course there were plenty of O1s who thought they knew it all, I enjoyed watching the events unfold. They were much more approachable to some critique and mentoring once they fell flat on their faces.

I would honestly say that I believe that CPL is the hardest rank;
-belong to NCO Corps, and have the duties of an NCO but paid as a SPC
-Everyone expects you know know your job to perfection but they don't think your good enough because your "only a CPL"
-E-4's don't respect you as much because you are the same pay grade
-And last but not least some E-5's believe your not good enought.
That is just my experience through the years. Never have been one but was around a couple