"Mind your Ps and Qs" is an English language expression meaning "mind your manners," "mind your language," "be on your best behaviour," or "watch what you're doing."
eg. I have to mind my p's and q's when I'm with my grandmother.
It's hard to pin the origin. But It might be related to learning the alphabet. As the first is in a poem by Charles Churchill, published in 1763:
"On all occasions next to chair
He stands for service of the Mayor,
And to instruct him how to use
His As and Bs, and Ps and Qs."
- From online (with editing)
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Our neighbourhood used to be a large foothill farm. In the 60s, the university was built next to it; then the farm land was subdivied and houses were built one by one. The descendant of the family is still living here and has been selling flowers 3 seasons of the year from their homestead.
All the animals who used to live here, deers, ducks, rabbits, owls, birds, ... etc., don't think, as nor agree, with our behaviour. They have been trying to come back year after year. A deer family even made a permanent sleeping pad in one elderly neighbour's back yard.
I like animals, as said in my last post. But my plants are afraid of of the big ones. So we fenced the side and back yards, and I planted deer resistant plants in the front.
But I got a surprise when I went watering my front garden this morning: Ahh??? more than half of my crocosmia flowers have been eaten (pic below) !!! 
Dear deers, would you please "mind your Ps and Qs"? 
