Consider another nice Polish saying "Zamienił stryjek siekierkę na kijek" that literally means "Uncle replaced hatchet with stick" but I managed to form it into a little rhyme just like in Polish (I know it doesn't rhyme very well or at all). It goes: "Replaced an uncle hatchet with cudgel" (not the bludgeon or baton). I'm looking for similar word/idiom.
This ironic and playful saying is mostly used to describe a situation in which one has made a very adverse exchange/replacement. It's been made completely unforced and as comments below say it's a regrettable choice because one thought it'd be good but it turned out to be opposite.
- I bought that Volkswagen but sometimes I still miss my BMW. Heh, _________ [replaced a hatchet with cudgel].
Will you help me improve my little rhyme? :-)