I came up with one, but it only works if you’re actually old(er) than the other party:
Old age and treachery will always beat youth and exuberance.
I like “I was born in the morning but it wasn’t yesterday morning”
I’m struggling to think of one that incorporates threat level, as such, though
Psst. See post #8.
One of the (few?) nice things about getting older is there’s ever more opportunity to use that line at work.
Then you retire and start hanging out with the other retirees, only to realize you’re the youth and exuberance in that crowd. :smack:
Corollary: I was born at night, but it wasn’t last night
Oops. I still was happy to remember it myself, though.
The problem with learning from experience is you get the the test before you’ve had the lesson.
Churchill is reputed to have said about Clement Atlee who replaced him “A modest little man, with much to be modest about.”
The follow-up joke about the bulls, is the one where the bull jumps the barbed wire fence to get into the cow pasture, but leaves two important ornaments on the fence. One of the cows says “that’s OK, dearie. You can be a consultant.” (Told by someone in our company who did not like the parade of consultants)
Or the joke about the old rooster; farmer was concerned he was over the hill, so gets a younger rooster. The next morning, the young one is all tuckered(?) out, the old rooster says “Let’s have a race to see who gets to be top rooster - 50 laps of the barnyard.” They start off, for the first 20 laps or so the young rooster is falling behind. Then the farmer comes over, grabs the young rooster, and chops his head off. “Dang!” he says. “That’s the third gay rooster I’ve bought in the last two months!”
Joke about writing software: “It’s hard to make things foolproof because fools are so clever.” (More about the number of illogical random things people with no comprehension can do)
“He’s smarter than he looks.” (Backhanded compliment)
“If you can’t fly, don’t fuck with the eagles.” (don’t get too ambitious, don’t overestimate your relative ability.)
“Crazy like a fox” - well known expression that what we see as erratic behaviour may have a purpose. Foxes are supposed to be very clever. Also “there’s a method to his madness “ same idea. (Sorry if I’m talking down to you and you know this.)
Also
“I didn’t come down in the last shower” (of rain)
“I didn’t get this <Phd/Bachelors/diploma/etc> for helping little old ladies across the road”
“I’ve X’d more Y’s than you’ve had hot dinners” (for whatever currently relevant value of X and Y)
I may have been born at night, but I wasn’t born last night.
I didn’t just fall off the turnip truck.
This ain’t my first rodeo.
“I’ve been around the block…”
“I was [insert action here] since before you were born.” Indicates long-term experience.
What time [today] did you learn to drive?
To a guy blowing his horn in traffic: What else did you get for Christmas?
Not the brightest light in the chandelier.
Not the sharpest knife in the rack.
One card (or several) short of a full deck.
Some thing about precautions against someone who is like “a cornered rat” might be germane to OP.
Ditto about watching out for she-lions/bears and cubs.
I used that one as the literal truth a couple of times back when I was working.
All your examples are great, and this one I like the best. Although the opposite one (retrograde?) about brainfarts seems a little baroque–and far too meaningful–for such a day-to-day event. My scenario (based only on the words, not how the good people of Spain take it): two movie cops returning to action-decisive-kick ass (illegal) form, in a "no more Mr. Nice Guy/Miranda/Search and enter mode.
Here’s some advice. Don’t put your trust in revolutions. They always come around again. That’s why they’re called revolutions.
Pets are always a help in times of stress. And in times of starvation, too, of course.
Geography is just physics slowed down, with a couple of trees stuck in it.
With due acknowledgement to the late Terry Pratchett.
One, we like baroque 
And two, it’s for the kind of brainfart that’s more “I should have remembered people can’t be trusted even when they’re decent” than “I should have remembered that word”. For example: it wouldn’t apply to not remembering how to do square roots (“uh… you use the calculator?”); it would apply to asking a client how he does X and taking his first response as the full and complete truth (even if they are being truthful, which is generally the case, there will be important things they leave out; there will also be things they swear up and down they never do and later “never” turns out to be “three times a week”).
Wisdom is the booby prize, they give you when you’ve been unwise!