What do you get out of it? Is he vain or is he saying “flattery will get you everywhere?” I can’t say for sure without knowing the context of the sentence. What was going on when this was said? Is he teasing? Is he serious?

It’s a quote from Otto van Isch. You might look him up to see how he meant it.

You can use this from the complimenter’s viewpoint also–a good way to engage someone in conversation is to compliment them about something simple and ask them a question that involves them sharing a story of something that happened to them or involves them sharing an opinion. Stay away from politics and religion and most people will be happy to talk your ear off. Pets, jobs, hobbies, etc. are nice to begin a friendship–the other person won’t be bored talking about themselves and perhaps you’ll find out you have something in common.

To understand the quote, think of a very handsome person who likes nothing better than to hear pleasant things about him/herself.

In other words, his favorite subject is himself.

“I have yet to be” means you have not yet encountered a situation where it was boring.

I.E. YOU LOVE COMPLIMENTS.