It was back when Apple had just introduced the (now-abandoned) Force Touch feature (i.e., pressure sensitive touch, since abandoned, since it turns out pushing hard on an unyielding surface is not very pleasant or useful).

To showcase the capability, Apple had updated many of its apps with new force-touch features. One of which was mail: if you pushed just right on the subject line of a message, you'd get a tiny, unscrollable popout preview of its contents.

It was totally useless: it took just as much time to force touch to see the preview as just normally tapping to view the message, and the results were less useful. It was also fairly fiddly: if you didn't press hard enough, you didn't get the preview; if you pressed too hard, it would open into the full email anyway.

So Tim Cook, demoing the feature, said a funny thing. He said, "It's great, I use it all the time."

Which maybe, just maybe, is true, but personally I don't believe, not for a second.

So since then, I've had Tim down in my book as basically a big liar.