"Oi," John protests the bump, halfhearted, and shakes his head. "I could never have anticipated that."

At least not seemingly out of the blue, and that was all in jest and not about getting anyone to talk. So he really could never have anticipated it. But he will, of course, be far less surprised about it whenever Sherlock does it again, now that he knows.

Still, he won't actually be able to predict it or anything like that.