One of the biggest drawbacks of having hardware buttons on any device is that they are prone to breaking over time. Although my Apple Watch crown didn't break, I did occasionally notice it getting a bit sticky when I scrolled with it. Either I feel more resistance or it freezes momentarily. This is likely due to small particles trapped between the crown and the watch case. Even sweat can do a number if you tend to exercise with it.
Apple knows this is a problem for some people, potentially recurring, and has a solution. This isn't what you'd expect, however, especially if you own a Series 1 Apple Watch that was never advertised as being waterproof. That said, it works for all Apple Watch models.
That's right, the official way to loosen the Digital Crown is to run it under the tap, or at least warm water. Don't just do it. Apple describes a specific process to follow so that you do not run the risk of damaging your Apple Watch.
Make sure to turn off your Apple Watch first. Let it turn off completely and if you have it plugged into the charger, remove it. Also, if you're wearing a leather strap, remove both ends to avoid damaging the material.
Now position the digital crown under the tap and let it run very lightly. The water should be lukewarm. Try tilting the Apple Watch so the water falls just above the crown and then into the sink, rather than getting your entire watch wet.
While the water is flowing, rotate the crown several times and also keep the button pressed. Apple recommends doing this for 10-15 seconds, but I did it for about 20 to be sure.
Finally, wipe down the Apple Watch with a lint-free cloth, ideally microfiber. Let it air dry for about five minutes as well before turning it back on just to be on the safe side. You should now notice that the Digital Crown is working much better, hoping you've cleared out all the previous debris. If the problem recurs, you can always repeat this cleaning process later.
Personally, I've had success just putting my Apple Watch down while I'm showering and letting the steam get to it. I don't take it in the shower with me, unlike Tim Cook, but I keep it on the bathroom counter. The crown seems to loosen up a bit after recovering some of that moisture.
If nothing works for you, you can always take your Apple Watch to a local Apple Store and ask someone at the genius bar to take a look. Unless you need a brand new watch or watch part for some reason, which is unlikely, it should cost little to no expense for a quick crown repair. P>
