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. A showerthought should offer a unique perspective on an ordinary part of life.
Maybe because the oldentimes r/showerthoughts was explicitly NOT for thoughts that came to you in the shower. They were kinda strickt about it and stoned your snoo to death if you dared.
Every super big subreddit devolved into places where only the mods and their friends were allowed to post. Everyone else's would be deleted and then pointed toward extremely vague rules that literally could have multiple interpretations depending on the context. Like you'd post to Pics and it would be deleted for being an odd numbered size in kilobytes or a non standard resolution.
Then where are they even having thoughts? I don't think the location is what's different. I think they're just on different drugs.
ELI5