To hear complaints with patience, even when complaints are vain, is one of the duties of friendship.
I don't think anyone gets bored of being called good-looking. We are all vain in one way or another.
I can't let my mother's death have been in vain. Democracy is the best revenge, and we will have it.
And if you find everything as soon as you look for it, you find it in vain, you look for it in vain.