I walked up and introduced myself and said that I was a big fan, appreciated his hard work, etc. He looked at me coldly and just said "so are you going to buy something?" and motioned toward the booklets. I didn't need a printed copy of the `sed` man page so I shrugged and he seemed quite annoyed, turned to his assistant with a notebook computer and started dictating something to them, as almost to make it clear that our interaction was over.
I'm not sure what the point of posting this is, but that's my RMS story - it was my first "never meet your heroes" moment, I guess.
So I walked up, I introduced myself and asked a question about the freedom of _data_ versus the freedom of _software_, and without looking up to me he said "I don't do smalltalk". So I got back to my seat and told my "story" to my immediate neighbors, who were keen to learn what he'd said.
(He is much more constructive by email.)
One explained me that they are bombarded non-stop by people for years and years and at the end they'd rather be mean than "waste" their time on the rare chance of having a meaningful interaction.
The overwhelming majority of their interaction ends up with people asking them for opinions about their projects, collaborations, etc, and it gets so tiring that they statistically prefer to lose the chance of having a nice meaningful interaction rather than take the chance of yet another waste of time.
I know it's mean, but I get it.
Not saying they are all like that, just saying it's quite common among famous developers, they are bombarded non stop by people wanting to chat.