That's really sad about Andy from Depeche Mode. I love Depeche Mode.
Everybody has a crummy day and I'm very forgiving about that. Andy Fletcher may have been having one. I was glad that I encountered Billy Corgan at least once when he seemed happy. I'm sure that everyone can have their off moments.
I once ran into Isobel and Stuart Murdoch from Belle and Sebastian on the street. I had NO idea they were a couple...I was perfectly nice, told them I loved their music, and gave them some directions before sending them on their way. Later on I heard about all the drama they were having on their tour and that dates were cancelled because of Isobel. I probably interrupted a moment when they needed alone time, but they were totally cool.
Luscious Jackson were at a meet and greet, which is why their crappiness was even more out of place. If I just happen to meet someone, I try to be forgiving about their demeanor if it seems "off". Usually people are reserved or kind. Some people act like they're your best friend. Joe Strummer did that with my sister...he bought her a drink. The Chemical Brothers invited me and friend backstage like we were invited over to their house for drinks. Dennis Danell from Social Distortion was one of the nicest, most welcoming people I've ever met...I interviewed him by phone and he told me to come find him at their show. I figured he wouldn't have a clue who I was but he invited me on the band's tour bus and they signed stuff for me. The reality is most bands know without their fans, they wouldn't have careers. I've heard that the Arcade Fire peeps are a bit of a handful. That story doesn't shock me.