A Matter of Change

No, this post is not about something important/relevant/serious. The title is misleading, as usual.
It's about a strange thing that I've noticed in people. It's got to do with that fact that NOBODY, ever gives me change for a 100 rupee note. Whether I ask a shopkeeper, hawker, auto-driver, bus-conductor (who by simple deduction should have LOADS of change) or even well-dressed passers-by, the result is the same. They look at me as if I'm selling contraband (Psst... wanna buy some stuff???) and shake their heads. (I'd use a few choice words to describe their heads, but that's the subject of another post) At first I thought that it was the fact that I was speaking English that was the problem. Nope! Kannada and Hindi requests (yes, yes, laugh away - but I do speak other languages, and quite legibly at that) end up eliciting the same damn response.
For heavens' sake! it's not as if I'm giving them a fake note. They can check it if they like. It's as easy as holding the thing up against the light and looking at the conspicuous security thread. The note is most definitely genuine. This isn't the 60s anymore, where a Rs 100 note was a rare item, prone to forgery. Further more, do I look capable of a crime? I mean, seriously, look closer. I barely look 18, let alone a hardened forger.
What then, is the issue with helping someone acquire a bit of change? From any angle, changing notes looks beneficial to all the parties concerned. Person A in need of change, gets it and Person B replaces a bundle of notes with a single note. (highly beneficial, considering the fact that Person B a.k.a shopkeeper/conductor/hawker has an excess of change, which he/she isn't possibly going to need) I've tried to come up with an explanation, but I can't seem to find anything apart from the fact that people are just plain rude.