Many, many people who will attempt spells or rituals will bomb one at some point. I’ve done it. Everyone I’ve known has. There’s no shame in it, it’s all part of a lifelong process of experimentation. The only shameful thing is not using it as a learning experience!
Before I go into this, let me preface it by saying that I’m of two minds about the concept of a spell “backfiring.” Some schools of thought hold that backfiring isn’t really a thing — if you’re treating your ancestors, deities, and spirit guides like you ought to be, they’re not going to let that happen to you. Others hold that you absolutely can screw yourself over despite their best intentions — spirits are there to guide and help you, but self-sabotage is absolutely possible. In my practice, this plane is where things really manifest, so it is entirely possible to willfully mess yourself up if you try hard enough. By that same token, I also think that it takes a lot to do that. (I have seen it happen, though.)
So! If most witches are more or less guaranteed to experience a failed spell at one time or another, why does this happen?
Marble Crow 