I remember having the idea to use a mower like that as a basis for a loader, and then found Xfaxman's TORO thread and felt so affirmed about it that i didn't even need to do it myself afterwards.

I don't know if that's how it's supposed to work, but now there's nothing left to prove about it so on to the next idea.. And i REALLY want a mini telehandler as an all-around machine (including digging), so here I go finding Xfaxman's V417 thread, which has to be one of my favorite threads on a tractor forum. But i'm still looking for the way to put it together myself for 10k.
As far as use vs abuse, usually the stock hydraulic pressure is set so that you can't damage the loader just by pulling the control levers, IF you're loading the loader evenly from side to side (not all on one side) and IF the force in the bucket isn't concentrated too heavily in one area (lifting/prying).
Not using MOMENTUM for ANYTHING is a huge one which has already been said but probably bears repeating. If you have to bump/ram it you're in the danger zone where operator talent/technique becomes the difference between whether it breaks or not. You'll see people doing it and getting away with it just fine, but they're not the ones who 'have to ask'. Mechanical empathy will let you run something past its stated limits, but it's not something you develop overnight or without cracking some eggs along the way. When things are rated, the way they're rated is "what's the max weight etc that the Lowest Common Denominator Operator can do with this thing without us having a warranty claim on our hands?". When you get a lot gooder than the Lowest Common Denominator Operator, you can go way past that.
Me being a mechanic who likes to modify things, I take great joy in finding the limits of machines because i can
change those limits, and more importantly..
I can clean up my own messes without breaking the bank. For example, I've cracked a lot of pistons in my turbocharged vehicles, but i never paid anyone else to replace them, or i'd have stopped at the first one! So IF you can physically or financially afford to make mistakes, do whatever you want. But if you can't or don't want to, keep that time and money you don't want to spend in mind when using the equipment.