What you have to understand about the large toos, and these particularly apply to the 3 most difficult - M2s, U2s and Tritons...
These are flock birds, that live in flocks of 100+ birds, and are hard wired for that kind of, quite literally constant, day and night companionship... That's why they do so well as animal ambassador type rolls. The San Diego Zoo had one out front that greeted everyone who walked in the gate for 90 years, until it became critically ill and couldn't do it anymore... that was as well adjusted a bird as could be.
They simply don't get enough stimulation in captivity most of the time. Ergo, they turn into scream n plucks...
Yes, they have to be taught to play on their own, because play, like everything else is a flock activity.
Hold an M2, or a U2 too much, and you are in hell. DON'T SET ME DOWN AGAIN EVER!!! I WILL SCREAM MY HEAD OFF FOR HOURS ON END IF YOU DO... Like 15 hours a day, non-stop, ears bleeding, jet engine noise, neighbors calling the police and having you arrested loud!
Tritons are sweet birds, but they can be major league tantrum throwers.
A too with "spoiled bird syndrome" is the hardest animal in the world to rehab. They will "out suffer you" to get their way.
And yeah, when you see the ones that pluck themselves to the point where they are grocery store chickens, with festering sores all over, THOSE are the kinds of birds I ended up working with, and it wasn't pretty...
I love M2's to death, but I wish to god they'd never been introduced to the pet trade, because 95% of the people that get them are simply not capable of meeting their needs... and the results are just horrible to see!
With the three species I mention, I caution people, that you don't really know what kind of bird you have, or how good a job you did raising him til the bird turns five... that seems to be when it really kicks in.
THEN it's either heaven, or 80+ years of HELL!!!