BMyers, hang in there! If I had a nickel for everything that I have screwed up in my shop, then I certainly would have a lot more play toys!! It's sad to think on the money that has been wasted for seemingly stupid mistakes, but as the others have said, I chalk it up to the price of education. Nothing in life is free, including experience!
When I make a error (a mistake is when you don't learn from it) in the shop, I do two things. One, I analyze what went wrong in the first place, and two I try to come up with a method of "rescuing" the item from the scrap bin. Many times, whether it is salvageable or not, I find that I have come up with creative ways to accomplish a task that I would have not otherwise taken the time to ponder. I can always point to the thing that caused me the error in the first place, and all of this has improved my confidence and skills over the years.
On throwing stuff; I try to refrain from that. Admittedly I have done it before, and likely will in the future, but I view it as a bad habit to be in. Flinging an item across that shop may get you or someone else hurt one day, or maybe destroy an object of value. In my humble opinion, it isn't worth the risk.
So, take this instance and charge forward. Don't let it discourage you. Learn from your error and apply it to your future work. In the end, errors will make you better at your craft!