A series of jokes written for Giants that only they would understand

An Englishman, an Irishman, a Scotsman and a Giant are all standing around talking about Quantum Physics. The Englishman says "Once Cern is working properly, everything will change". Just then a plane flies past and distracts the Giant, and when he turns back to continue the discussion, he realises he is all alone.

Two Giants walk into a pub. The first one says to the Bartender "Where've you gone then?"

A Giant goes to the doctor and says "Doctor, Doctor, I feel like I've accidentally crushed to death everyone I've ever known or loved". The Doctor says nothing.

"Knock Knock"
"AAAAAAAAAHHHHHHHHHH"