Had the very same experience. I use 35mm and I had been looking for a fast wide-angle lens for a long time, even though I already own one. But I fell in the trap of "this is sharper". Well, I bought a new lens in the end, only to sell it back couple of weeks after. It was a good experience, I think I know better how to look for equipment I really need. What Iīm trying to say is, donīt worry, we all make buying mistakes or misjudgements. And often we tend to have more than what we actually use.
I guess you're right, though these are costly mistakes =_=;;