Who are you trying to impress.?

It came to my attention the other day that this girl I was talking to had no idea what band I was even talking about. She pretended to like to them and agreed with everything I said about them, even when some painfully obvious things weren't true. It bothered me for the longest time because I couldn't figure out why she was lying about something so silly. Then a past teacher of mine, that I still talk to, said she was probably trying to impress me with liking the same things.
Well here's the thing, so many girls and boys are like that, it doesn't impress people that you lie and pretend to like something you don't even know anything about. It much more impressive to be yourself and honestly be like hey, I have no idea what you're talking about. The guy might actually take some time and show you what he's talking about so then you have like bonding time with him and you can get to know him during that.
Who was she trying to impress anyway? If it was me she certaintly didn't do a good job of it.
Have you ever tried to impress someone by pretending/lieing to like or know stuff about something they're talking about?