I had 2 interactions with Neal. One at my LCS and one at a convention. Both times he was very nice and personable. Got some prints signed by him and he would tell a story about each print I got. At the convention, I had to wait until a local news crew was done interviewing him and he apologized for the wait. Couldn't have been nicer.
As far as creators/artists being nice to an unappreciative fan (well, not really unappreciative, just young and dumb), that would have to be Bob Layton. I went to a con with my nephew. He asked me what I wanted to get. Told him Bob Layton was there and I wanted to get an autograph. He asked who he was. Once we got to the con, I showed him some Iron Man covers. He replied "He's not that good". Took all I had not to backhand him right then and there. SO, little bit later, we run across Bob sitting as his table. NO LINE! I walk up and start talking with him and grab a print for him to sign. He asks my nephew, who is looking around, if he sees anything he likes. I tell Bob that I showed him some covers and he didn't think they were that good. Bob laughs and looks at my nephew and says "here take a look at this". He pulls a portfolio out from under the table and hands it to my nephew. As he is looking thru it, we can see his jaw drop and say "WOW, you are good!" Bob laughs and says, "yeah, my mother thinks so too". What a fantastic guy to deal with.