What does Holden say about his ex-roommate who was a terrific whistler?

From the text:

Naturally, I never told him I thought he was a terrific whistler. I mean you don't just go up to somebody and say, "You're a terrific whistler." But I roomed with him for about two whole months, even though he bored me till I was half crazy, just because he was such a terrific whistler, the best I ever heard. So I don't know about bores. Maybe you shouldn't feel too sorry if you see some swell girl getting married to them. They don't hurt anybody, most of them, and maybe they're secretly all terrific whistlers or something.