YouTube videos can be pretty long and run up to 10 hours.
There may be a specific moment in the video you may want to show your friends without having to sit through the rest in its entirety. To do that, pause the video at the moment in question and select the Share button. A pop-up will appear with a URL, but before you copy or share it to social media, tick the box underneath it to start the video at the moment you paused it. The URL will instantly modify itself.