A "Showerthought" is a simple term used to describe the thoughts that pop into your head while you're doing everyday things like taking a shower, driving, or just daydreaming. The best ones are thoughts that many people can relate to and they find something funny or interesting in regular stuff.
People still chewing gum, but chewing gum is no longer a fashion trend. So they don't purposely show to you that they are chewing gum.
I do chewing gum when at work, to help me stay focused. I don't chewing gum while hanging out with friends to look cool, because it no longer a trend. Beside, it is not comfortable to speak while chewing gum.
Was watching a Steve Ramsey video on YouTube today and noticed he was chewing gum through parts of it. Made me think of this post again. You definitely don't see a lot of YouTubers chewing gum!