It'll take some doing for anyone to beat the long conversation I had to have, years back, with a representative of a very large film studio, who were concerned that a domain I'd registered might verge uncomfortably closely on their mark.

Worked out in the end - it only took them a few minutes actually looking at the content to realize, on the one hand, that it was clearly not being used for any commercial purpose, and on the other, that there was no meaningful risk of confusion between my domain name and their mark. They were happy to wait to buy it until I was done with it. But it was a surprising call to receive at seven o'clock on a Saturday evening!