I'll add a couple more who were fantastic: Arlene Martell, Natalia Nogulich, Don Marshall, Gary Lockwood, Armin Shimerman. All of them were wonderful. Kind people. Extra kind to my kids who have accompanied me.
A couple of non-trek actors who were spectacular were Herb Jefferson Jr. and Richard Hatch from the original Battlestar Galactica. The friendliest, most approachable gentlemen I've ever encountered.
There are a lot of other outstanding folks I've encountered, Trek and otherwise. I've found it really the rare exception who isn't at least cordial. Even the couple of times I met Brent Spiner, he was nice enough. At least, he wasn't mean.