Beware the implications of checking your watch, it may have a negative social impact.

If you are on a date, in a meeting, or at a social event, you should not check your watch visibly in front of other people. Similar to it being rude to check your phone at the cinema or restaurant, checking your watch shows that you have other things on your mind, things that take precedent over your present company.

Besides, the only way you should know what time a date is over is when she says goodnight.