I have a big paper to write, so naturally I'm on here writing this intead...
I've only seen her live once, and it was at Ann Taylor for Fashion's Night Out last year (I was front row center - if anyone else tells you they were, they're lying hahaha). I didn't meet her per se, but she certainly didn't come across as a snob to me. While she was coming onstage, she walked right past me to get to the stairs (kind of weird that she had to walk through the crowd, but again it wasn't a real concert) and I said "hi, Vanessa!" really awkwardly and she said "hi" really awkwardly back. Epic XD
After the "concert," she came back down the stairs and walked through the crowd. She didn't walk very quickly, but it was clear she wasn't going to be signing autographs, taking pictures, etc. The person next to me was crying (tears of joy, I guess - seems a bit odd to me, but I guess I'm not a superfan haha), and her friends were like "take a picture with my friend, she's such a big fan!" It was clear Vanessa didn't want to, but she didn't want to be rude by being like "NO" so she was like "whaaat?" and acted like she didn't hear them, hahaha. I then said "thank you" for the concert and gave her a little wave, and she waved back kinda as she walked off, and then she went downstairs to the VIP room (how many VIPs went to Ann Taylor that night, I can't imagine XD). But yeah so no real interaction - actually I think she interacted with me more than with anyone else hahaha. Yay for being assertive!
I mean, in her defense if you have to take a picture with one person, pretty soon you have to take a picture with EVERYONE, so it's not fair to do something for one (crying) girl that you won't do for anyone else. But yeah, she didn't really interact with us. And again in her defense, a lot of people were talking while she was playing - at one point she was even like "this is a soft song, so I'm not sure if I should play it since it's loud in here" (she was talking about London), so if I were her I probably wouldn't have been in the mood to interact, either.
Just my experience, I felt like sharing. I thought she was perfectly nice, even if she didn't go out of her way to interact after the show. I would've liked a picture, but I understand that these things happen. It was a great concert, by the way! Ari was looking goooood.
tl;dr: The takeaway is that she's a real person. Sometimes she'll interact, sometimes she won't be in the mood to; sometimes she'll be outgoing and funny, and sometimes she'll just play her beautiful songs and not stay after.