Client: The site isn’t accepting a date I’m trying to put in.
Me: What date is that?
Client: November 31st 2014.
Me: Oh, that’s because that’s not a valid date.
Client: What do you mean “not a valid date?” It’s an annual event and an important date to me. What’s changed that it’s no longer “valid?”
Me: November only has 30 days. Always has, as far as I know.
Client: …you should put a note on the website to avoid these situations.