T-Rex: It turns out horses aren't the only inspiration English uses for its idioms. We also use... doors?

T-Rex: OPPORTUNITY knocks on doors, you guys!

T-Rex: And when Opportunity closes a door, it also opens another. Sometimes, SOMETIMES, it opens a window.
Dromiceiomimus: These could be classified equally well as "idioms involving abstract concepts somehow granted agency".
T-Rex: Ooh! Like when Fortune favours the bold! Or when an ounce of Prevention is better than a pound of Cure!

Utahraptor: ...Gross.
T-Rex: Yeah, that's - that turned out gross.

Utahraptor: Anyway! I think all we can conclude is that folks talk about the things around them, and horses were around us for a really long time. And THAT suggests that millions of years from now, there'll be lots of aphorisms about transporters, spacebots and cyberdroids!
T-Rex: AWESOME
T-Rex: I CAN'T WAIT

Narrator: MILLIONS OF YEARS LATER:
Off panel: Attention patrons:
Off panel: Our paleontology exhibit closes in five minutes