Paula Radcliffe. Super nice, down to earth, no different to how she comes across on TV.
Chicago 2018, in a hospitality tent a couple of hours before the marathon, my wife spotted Paula stood alone drinking a coffee. There was hardly anyone around. After a minute or two debating whether to approach her or not we decided to go over and say hello. She was very friendly, spoke to us for several minutes, happily posed for a pictures. Paula seemed to show genuine interest in my marathon training and couldn't possibly have been nicer.
The next day we spotted Brigid Kosgei browsing through clothes in the kids section of the Nike store (we found out later she had twin children). It super busy because they were engraving medals for free. Yet Kosgei, who had won her first WMM less than 24 hours before, seemingly hadn't been recognised by anybody else at all. I congratulated her and she posed for a picture, but Brigid was very shy and could barely understand or speak English. She was polite, but clearly uncomfortable being approached by a stranger, I got the impression she would much rather have stayed anonymous. I felt a bit bad that I'd bothered her.