Incomprehensible expressions

[Dilbertian]

I think I've worked out what these mean, but why do they mean that?

Crickets - silence
Fill your boots - if you like
Lose your rag - lose your temper
Go postal - do something in anger

Have I got them right? And why do they mean what they mean?

Please also post any expressions that puzzle you!

[RoachTheHorse]

Crickets is presumably because it's so quiet you can hear the crickets chirp.

[facefit]

The postal one refers to postal workers in the US losing their rags and shooting up the place

[Dilbertian]

@facefit

The postal one refers to postal workers in the US losing their rags and shooting up the place

Surely it's too tasteless to use?

[InsertPunHere]

Crickets are to emphasise there are no people talking. Silence, in which you hear the crickets chirp.

[InsertPunHere]

And no, the PP is right, it was the cliché that the crazy guy in the clock tower shooting people is a postal worker.

There’s even a bit about it in the Steve Martin film Parenthood.

[butterpuffed]

I've always known 'fill your boots' to mean 'eat as much as you like'.

[facefit]

Wiki

[LemonDrizzles]

Keep an eye out for something - looking out.

If your eye is out, surely you can't see...

[TastesLikeFlavourlessFizz]

Fill your boots means to do/take as much as you like of something - which included but is not limited to food.

Miners used to fill their work boots with coal at the end of the day and carry them home.

[OhDearODear]

‘Shoot the breeze’ is one that’s popped up a lot recently.
I prefer to think that ‘fill your boots’ relates to looting in time of war: carrying off everything available in anything available.
I’ve never heard ‘crickets’.

[Dilbertian]

I thought ' fill your boots' has the same source as 'bootleggers': illegal booze being hidden in smugglers' wellie boots.

[OhDearODear]

I think ‘fill your boots’ is a British expression whereas ‘bootleg’ is American in origin.
I can see ‘fill your boots’ being used in a ‘Whisky Galore’ sort of situation.