The questions kinda mesh together in a wonderful way, so I'm going to just summarize.
It's an elevator pitch.
If a stranger walks up to me and sees that I art to the extent that I art, and says
"Can you work for me for free a pretty hefty project I've been daydreaming about on and off about. I've also imagined getting rich/popular because of it."
I'm not really feeling it.
It's the amount of trust I have for a person. It's how important that person makes me feel.
"Work for me because you're an artist and I have a dream." Isn't super thoughtful, especially if it's a first impression.
A small-size, thought-out project by a close friend or popular person who I can see evidence for in their work, has a chance. This has to pitched in a competent, clear way. Hazy, floaty daydreams are adorable to hear about, but not something I want to pour hours of man-power into.
I've only had a few instances, and they aren't fun. Essentially, it's someone who I didn't really talk to in class. Once they figured out I drew, they cornered me and talked about this "big project" they were working on for years. When I asked what it was about, it was "a little complicated", and like insert anime here. Honestly that's fine, but the sudden enthusiasm after figuring out they could get something out of me, made me feel pretty bad. Also the project was a entire comic series, instead of character concept or a cover idea.
If you work hard on your pitch, you'll seem more reliable, I think.