Fancy technology hasn't thought of everything.

If you have a tattoo that covers the part of your wrist where a watch would go, the tattoo ink may cause the Apple Watch to not function properly, according to people who have both tattoos and problems with the watch.

If the wrist detection tool cannot identify the skin of the wearer, it shuts down because it assumes it has been taken off. The sensors use light to read heartbeats which tells the watch it is being worn, but tats with darker-colored ink wreak havoc with the sensors. This affects several key features of the Apple Watch, like their Apple Pay service.

You can disable wrist detection, but it makes the watch less secure.