I wore a high and tight all last year while activated with my reserve unit. I had the opprtunity midyear to go Marine Corps Regs and did so. As a Navy Doc I did everything else with them, why not dress like them too. Got my entire uniform issue, and my unit failed to put it in my record. Then they told me I wasn't Marine Corps regs. I asked them nicely/respectfully to fix it, they didn't, so I grew my hair to Navy Regs, a few inches of loft, sideburns. They still failed to change it. It was kind of nice to walk around an not be pegged for military. I didn't have all my gear in bags emblazoned with my branche's logo all over it, as many did. The seabag was not my "luggage" as many chose it to be. With all the time I spent in airports, OPSEC just seemed to be the smarter move in the event driven terrorist awareness climate of last year.
But it made my Gunny mad. That was kind of worth it.
It's not the haircut that gets people cranky, wear whatever you want.