In your opinion, what is the most common violation of uniform regulations, and are you guilty of it from time to time?

Out of Reg boots, hands in pockets, No show socks, hair out of reg.

I bring it to their attention that they are Ate up, but I don't have power to reprimand or correct directly. I don't do these things, because I would rather be the standard. I'm also a Paralegal Specialist, with the Trial Defense Service and we have to keep our clients in Reg for their boards.

Not just AR 670-1, but across all branches: using our Air Force gloves, AKA hands in pockets.

Though SGM (Join to see)'s statement rings true too. There are actually circumstances in the Navy uniform regs that allow for hands in pockets, yet people don't bother reading the reg and learning it.

Most common I see are people wearing boots that are out of regulation.

Without a doubt, the violation I see most is back pockets unbuttoned, often with the pocket flap tucked in.

Hands in pocket is the violation I was most commonly guilty of. This was really only a big issue in Class B uniforms and the old fatigues. Once we got BDUs and DCUs, putting hands in pockets required a level of stupidity that even I could not reach.

Nike boots. But they're soooo comfy.

Lets see, which regulation am I violating the most? I don't wear Army issue underwear, because I wear sport briefs. I made the change on day one. I actually forget to shave sometimes but not a single soul will notice. I do keep a spare shaving kit in my car.

hands in the pocket without a doubt

When I was on on active duty it was hands in the pockets. Badly pressed BDU's. Mixing uniforms when off duty. Best one for me as a GS 12 was when I was deploying to Kapasvar after the Bosnian war to get all that excess put back to the USAREUR books. Walking to the bx a air force major yells out hey soldier where is your hat? I turn around and says o shit your a civilian. That's right jerk. If I was a soldier you should have handled this a little less dramatic. A couple AF sgts heard it. Came up to me and said he is a jerk. I said I know I am a retired cw4. Good judge of character.

When you're Sgt AR670-1, you never have uniform violations, and never put your hands in your pockets.
Always made OTS corrections. I didn't let anything slide, attention-to-detail. Never made a correction unless I could quote para and line verbatim. Juat my standard. Yes, was as familiar with my TMs, FMs, and SMCT. Didn't have an appreciation for someone who knew all the "rules," if they weren't as knowledgeable with their equipment, weapons, PT, DC, and tactical operations first.
Does a uniform violation make a Soldier a POS, it does no more than spit shined jump boots, a high and tight, and starched BDUs make a Soldier squared away. It teaches attention to detail, pride, espirit de corps, and keeps them from getting tore up by somebody when they are out and about. You're not going to give a Soldier an ART 15 for a uniform violation, well, I wouldn't, but can't help them much if they get disrespectful with the wrong person in civilian clothes, or uniform, at the PX. Although I note that the latest AR 670-1 includes the statement that violations are punitive. No need to let your Soldier be a pop up target.
During deployment, I never said anything about hands in pockets, or comfort violations in the immediate area. We were deployed with the Marines, so I insisted they maintain the standard everywhere else. I never had to make a correction. They did it out of pride. Plus, anywhere outside of immediate area required a SL be with them.
Some believed it was overkill, but I understood this was first regular Army many Marines had served with, and they were watching. After a couple of weeks, the 1MARDIV SGM joined me as I was eating lunch. He told me he had been watching, and watching hard, day and night, as he did with his Marines. He commented that my Soldiers were always in uniform, always had an NCO supervising, weren't horse playing or other "jackassery." I shared this with my Soldiers, who, then, got it.
My CDR and I were in Kuwait, and a Soldier in PTs had on religious headgear. My CDR didn't realize it was authorized, so stopped the Soldier to make the correction. As I was about to correct the correction, the Soldier responded, very flippantly, that it was a religious item, authorized, and he wasn't going to remove anything. I "reminded" him to assume the pos of attn, then informed the CDR that it was authorized, and asked for a minute. (CDRs cue to reach plausible deniability range). I further "educated" the SGT about disrespect to an officer, failing to assume the position, and that his belief that an incorrect OTS correction, was his opportunity to be disrespectful, religious item, or not, was a gross miscalculation.
My CDR left the OTS corrections to me when we were together after that.

As a new SSG, I made an OTS to the DIV CSM for having his headgear "Ranger rolled." Without breaking stride the CSM, popped it out, and thanked me. I got a coin. Thought I was going to get ripped.

When we returned to Ft Bragg after OIF I, AR 670-1 had changed to authorize specific Army units who serves with Marines during OIF I to wear the 1MARDIV as SSI-FWTS. I made my Soldiers carry a copy of the change while in uniform. I also instructed them to assume the correct position, listen, and explain the change respectfully and offer to show the copy. Several got stopped at PX and other locations, and all, but one, went well. A member of the unit SPC mafia called me, and explained he had done as directed, but a LT was demanding he cut it off. I educated the LT. He insisted that I was mistaken. I invited him to contact my CDR, and added my Soldier would not be further delayed.
I note that they've expanded the time period covering the wear of Marine SSI-FWTS.