Someone offhandedly mentioned to me that quantum computers are sometimes significantly (I guess they meant asymptotically) slower than classical computers. Unfortunately, I didn't get any arguments nor examples for this statement, and I'm not able to figure the limitations out myself.
I tried to look up articles on the web and questions on StackExchange, but everything is about the problems where quantum computers are faster. None of them mention how solutions to the rest of the problems compare in speed, at least not what I could find.
Question: What are examples where quantum computers are significantly/asymptotically slower than classical computers?