"Guess it's been pretty rude of me to avoid him all this time."

How very rude of me to keep you standing all this time.

"It would be rude of me to sit when there's only one chair."

It is very rude of you not to have returned my calls.

But it was very rude of him not to have said something, at least in greeting, before this.

It was perhaps rude of me, but I wanted to see what she would do.

I thought it very rude of him to get my sister's name wrong that way, but she didn't seem to notice.

Is it rude of her to expect us to do this?

I think it's very rude of them to come back and make another.

It was rude of me to order without asking if you wanted something to eat, too.