a guy walks in to a butchers shop and says morning can i have 2lb of liver plz butcher replies sorry fresh out of liver ive got some nice steak and kidney .....guy replies no its ok ive got my bike out-side lol
Have heard similar so say jokes before where there is no explanation. Its just made up to see if anyone laughs, then gets mocked when it wasn't actually a joke in the first place.
I think the funny bit is the mental image you get of the blank look on the butchers face.
It's a bit like going into a DIY store and asking for a screw driver and you get offered a hammer and you say, no thanks I'll use a paint brush.