Idioms relating to things impossible, inadvisable or otherwise to be avoided.

It’s bad, but it’s better than watching the grass grow (or watching paint dry).

And there’s no point reinventing the wheel, or using a sledgehammer to crack a nut.

I’m working on a project that requires a compiled collection of popular phrases and idioms along the general lines of the above… anyone care to contribute?

Better than a poke in the eye with a sharp stick.

I’m not going to touch this OP with a ten foot pole.

English only or can we go exotic?

A Spanish one: “to be more lost than an octopus in a garage.” It can be used when someone is literally lost or at a loss.

All suggestions are welcome (I won’t be able to use them all in the project - about which more later, I promise), although I am looking more for action-related idioms than the octopus thing (which, however, is interesting, so thanks for bringing it).

Huh, kferr got there first with the sharp stick.

Still, that’s better than a slap in the face with a wet fish.

We need this OP about as much as we need a hole in the head, and quite frankly, I’d rather gouge out my eyeballs with a rusty spoon.

It’s a small world - but I wouldn’t want to paint it.

At least you’re not trying to collect all of them – that’d be like pushing on a string, or pissing up a rope.

It’s better than being kicked in the head by a mule.

It’s no harder than pulling teeth – as easy as catching a greased pig.

Again I tell you, it is easier for a camel to go through the eye of a needle than it is for a rich man to enter the kingdom of God.

Dopers sure like to compare things to herding cats, but getting a comprehensive list of these dealies might be just a bit easier than nailing jello to the wall.

Don’t use a cannon to kill a mosquito.

Oooh, I just thought of one: You can’t make a silk purse out of a sow’s ear. Also, don’t make a mountain out of a molehill.

Replying to this thread is as easy as taking candy from a baby.

Ah, but that’s the opposite of what I want - taking candy from a baby is easy - unlike, say, selling ice to Eskimos.

I’d rather slide down a 50 foot razorblade into a pool of salt water than reply to this thread.

You could try selling used matches. Or sell spats to a snake, if you’re looking for something really futile.

This road is as rough as a washboard.

Around here it’s: As hard as selling a fridge to an Eskimo.

Getting a straight answer from you is as hard as skinning a cat.

You’re as bright as a burned out bulb.

You’re as worn as the bone the dog brought home.