Things you CANNOT do

I can pull my socks up, but I can't

- get my knickers in a twist
- eat my hat
- make a mountain out of a molehill

-look daggers

Blow up like a balloon (unless a bicycle pump is inserted ‘somewhere’)
Laugh like a drain

You can't be knocked down with a feather

Eat an elephant one bite at a time.

Pay through your nose (not yet anyway).

See right through someone.

Have a head that buttons up the back.

Literally, I shall continue to use metaphors when appropriate.

Love it, great thread.

Needed that, unlike a fish needs a bicycle.

Carry the world on your shoulders.

Turn green with envy

For the Glesca Grannies , remember the old clippies saying
come oan, get aff (Come on, get off my tram!)

CherryCezzy

Walk on air.

Sleep on a washing line.

Sorry, CherryCezzy, but the "sleep on a washing line" thing has some historical fact. People who couldn't afford a bed in a bunk house, were given a cheaper option of being able to drape their arms over a rope slung across the room, and sleep that way.

Get you knickers in a twist the Phoenix would know about that one ?

the ?

Love you to bits.

My mother used to say "Get your nose out of that book!"

Be a ray of sunshine.

Thanks for reminding me phoenix
Sleep on a washing line is not the sole example already posted that has an origin in historical fact.

Ah, how dull our language would be without such expressions

You can't walk on air. Even if you're wearing those very expensive innersoles in your shoes.

Be on cloud 9

Be on top of the world

Disappear up your own backside

Come up the Clyde on a biscuit.

Laugh on the other side of your face.

Laugh till you cry!

Eat till you burst!