I had a friend like that. For her birthday one year, I offered to take her out for dinner and was really looking forward to it, being kind of a stranger in a strange land at that point in my life, with few friends. When I called to confirm the time and place, she pointed out that I had mentioned having had a cold the week before. I indicated I was fully over it, and I was. Her response was: "still, I don't want to take any chances that you might spoil my birthday week [birthday week???]". She was 64 years old! I was crushed. We never spoke again.