I still cringe telling this, and it will put me, but here goes.
I used to work for the local council and we were doing some work around promoting food banks (as in where to donate, getting more donation points into public buildings, etc) as part of an anti-poverty drive. My boss at the time was one of these annoying over achieving David Brent types who would think of unachievable and ridiculous ideas and demand we find a way to make them happen, preferably yesterday. But she never did the work herself of course!
Anyway, one day she came in and announced that a certain celebrity chef (let's call him Bob for arguments sake, no resemblance to his actual name) is from the area, and wouldn't it be great if he would do a few videos blogs on how to cook a naice meal from food bank food. Nice idea in theory - but we had no budget, and this is a very famous chef.
Some tool from across the other end of the office says "oh my aunty's neighbour's cousin's son knows him, I'll get his number" 
not only did they get it but cheeky fucker boss made me call him. "He'd think it such a privilege" she said, "this is gonna be huge for us!".
In my defence at the time we were going through a brutal restructure and everyone was fighting for their jobs, so I couldn't feel like I could say no, or speak out about what a ridiculous idea it was.
So I called Bob, and i swear it was the low point of my entire career. I thought the number would go through to his agent but no it was his personal mobile number! So the conversation basically went:
Bob: "Hello?"
Me: "Is that Bob?
Bob: "yes who's this?"
Me: "my name is Gunpowder from the Twat team at Local Council, we're running a campaign to promote donations to food banks in the area and seeing as you're local I wondered if you'd be up for helping us out?"
Bob:..."how did you get this number? This is my personal phone? I'm actually filming right now"
Me/ "Oh god sorry I didn't realise, someone in the office got it for us"
Bob: "well I'm not happy about that, very few people have this number. What are you wanting me to do?"
Me: (cold sweats now) "Maybe some video blogs about recipes for food you can make with food bank food?"
Bob:"....right. So you want me to make some videos, presumably for free, in my own time, on your terms"
Me: "...erm"
Bob: "no is my answer. And destroy anything with my personal number on please. Goodbye."
My boss was furious that I didn't press him more and couldn't understand why he was so mad about calling his personal number. I'd thrown away a missed opportunity apparently 
I am totally mortified looking back that I did that, and pleased to say a few weeks later I'd found a new job! I can't watch Bob on TV though now