the host's lost key at check-in is manageable, it can happen to anyone. even if you want to arrive after a long journey before you take a round through amsterdam because you can't get in.
but we would have liked more understanding from the host. In the apartment above our accommodation there were two small children who greeted us with a loud trampling, as the ceiling is very noisy. we tried to get set up but 1 1/2 hours later they were still running. that is not a state that you would want for your vacation. but you can't and shouldn't prevent children from playing. after 3 hours in the apartment with running kids above we decided to book a new accommodation. the host wanted to talk to the family, but we had made our decision. because we neither stayed overnight nor actually used the apartment and given the key immediately after the decision, the host was not willing to compromise on the money. we lost both a day of vacation and 300€. and then to be told by the host that he could have settled the situation and that we left voluntarily was pretty tough. the accomodation was ok for a stay in amsterdam, but the handing with guest problems was recommended.