I hear you! Things like this happen to me too. I swear I hardly ever lose time or have a black out, where I am one place one second and the next thing I know it is a different place and time entirely. I mean it does happen, but hardly ever. Most of the time I think I don't lose time at all but the evidence of actions unremembered whacks me in the face a lot. I think most of the time it is things I just ignore and pretend don't happen at all... but then sometimes things like you with the sponge holder happen and for the life of you you can't dredge up any memory of it at all.
Things that make you go "hmmm"!
This was one of the things I relate to a lot from that post I did the other day about amnesia. its very tricky to know if you have it or not sometimes.