A nice double-level conundrum from My Actual Real Name, who says “Completely mystifying to me. Anyone have any idea at all?”
[Post title is excerpted from https://www.etymonline.com/search?q=terrier ]
“Typically small, active, hardy, and noted for their courage.”
Comics I Don't Understand 
Sedans: a once-popular but now-increasingly-rare type of car (in the USA) as people buy minivans, SUVs, crossovers, and pickups much more often.
Terriers: a once-pupular [sic] breed of dog, now increasingly rare, as people buy retrievers, poodle, bulldogs, etc. or proudly adopt mutts.
And the guy thinking in the shower indicates a Shower Thought (see https://www.reddit.com/r/Showerthoughts/ on Reddit), those little nuggets of profundity you get as your mind wanders while washing your body.
thanks, itsamike, giving it the Shower Thoughts name clears it up for me. I was trying to see how it could be somebody drifting towards sleep, tucked in for the night, but the picture kept refusing to support that
Terriers are my very favourite breed …
They’re easy to keep clean and to feed …
My shower thought is generally “I really should clean this shower.” :-)