I haven't met a lot. Malmsteen as a young man. In a DiMarzio booth, surrounded by guitar nerd acolytes. Contrary to reputation/expectation, he wasn't an arse. Cocky and confident, but he dutifully and earnestly answered all my questions about his then fresh departure from Alcatrazz.
I also met Tony Carey, the keyboard player from Rainbow's Rising album plus then an emerging songwriter in his own right. He was genial, but horny (well, I met him in the Frankfurt red light district, fair is fair). Had his Brit manager with him who didn't even know he had played in Rainbow. I was DJing in a peep show back then and put on the iconic synth intro of Tarot Woman, followed by one of his more current hits with his then Planet P Project. That had him puzzled at first and he finally came up to my booth and said: "You know me?" He looked very much like half the Native American he is - physique, cheekbones and all - and of course the ladies of the night would soon dub him "der Indianer". I still have his signature on the Rainbow Rising album.
Only a few years ago, I met John Wetton (friendly and charming, disarming), Steve Howe (a nerd, but not of the bad kind), Carl Palmer (talkative to the point of hypheractive - kind of like his drumming! - kept pestering me about my law firm career as his daughter is in one!) und Geoff Downes (workmanlike, enjoys his beer after the gig and had some sardonic comments about Yes to make), in other words Asia. That was nice and very relaxed, probably because I like Asia, but am not overawed by them. Meeting someone from DP, I would probably freeze or say the most mundane things to later on kick myself for!