I believe skill of crafting (IE tinkering for most tools and such, maybe woodworking and stone-working for others) has an effect on the quality of the crafted items. High quality gathered materials are just random, I believe.
Found another one with my game-breaking powers:
If you drop/throw an item with 0 decay remaining, the decay resets, essentially giving infinite decay time.
This works with torches too. If they are dropped, the go out, but if they are thrown, they stay burning.