During deployments in '04 & '06, I ran into Robin Williams twice on early mornings (along with some USO handlers who promptly went to stuff face); in a dusty, lonely, relatively small DFAC/chow hall, at one of the far-flung live-fire ranges in Kuwait.
Both times, he had come in the exit low-key, at the point where trays were dropped off. and started quietly greeting guys as they were leaving.
It didn't take long before the whole DFAC was listening to guys near losing their breakfasts with laughter & Williams loudly roasting/bullshitting troops as they filed out.
But he wasn't doing the G'Morning Vietnam bit; a couple clowns called for it, and he clowned 'em back. It was just him, and he somehow knew *exactly* how to make each individual either laugh or blush (the man definitely wasn't shy with the ladies, downrange rules for lulz were in full effect).
Then there's Gary Sinese. Aside from him & his band showing up wherever I landed during transits, I also met him twice walking the other way from a latrine/smoking area. Nobody recognized him & he looked like he was on a mission, so I just touched my brim & gave him a "Sir" as I went by. Aside from that though, if he had the time, he tried to talk with guys alone or in small groups whenever possible.
And how can I forget Drowning Pool; holy shit, those guys were *constantly* doing gigs everywhere S.W. Asia, and at Rammstein.
While waiting for a flight out, I ended up drinking near-beer with some Drowning Pool roadies at Arifjan on my last go-round. After commiserating about the sad state of our sobrieties; someone may or may not have smoked a little hash in the back of a covered deuce, in exchange for a little scotch, because it had to be done.