Focused. That's the one and only positive thing I can say about one-trick ponies. Aside from that, they're b-o-r-i-n-g.
Say, the ponies, "That's my thing, that's what I do." Well, good on ya! But - did you ever consider that maybe, just possibly, virtually no one else gives a rat's ass? Politics, religion, kids, food, dogs, clothing, whatever. SOS. Day after day.
The ponies publish their tricks on Facebook. When I see a pony's name, I don't need to read the post to know the subject matter. When I see a pony's picture, I instantly know the pony's name. And, in both cases, I quickly scroll past the pony-post in search of something new and interesting.
I've FB-friended numerous people, college friends for instance, that I've not seen in 50+ years. I was excited about reconnecting with them, getting updated on their lives, hobbies, travels, family, and so on. In surprisingly many cases, as I eagerly scrolled down through their recent posts I quickly discovered that they were one-trickers. I unfriended them soon after. Sad.
So, here's a challenge to readers that happen to be ponies: learn a new trick for cripes sake!