If it bit you in the ass : a less colloquial equivalent to it?

[Hetep-Heres]

Hello!

I'm currently looking for a more proper equivalent to the idiom "if it bit you in the ass (or arse)".
As in : "You couldn't know xxx (insert whatever you want) if it bit you in the ass."

I'd like to carry the same idea but without the informal / vulgar tone.

Could something like "if it hit you in the face" work? Is it a known / common expression? Do you have any other suggestion?

Thanks in advance!

 

[sound shift]

Yes, "if it hit you in the face" is in use and is not vulgar.

 

[Keith Bradford]

"If it bit you on the knee/ankle" are the versions I use.

 

[PaulQ]

To me, the idiom is: "You wouldn't know xxx (insert whatever you want) if it bit you on the arse (BE spelling of ass)."

I have heard: "You wouldn't know xxx (insert whatever you want) if it came up and shook hands with you."

 

[Hetep-Heres]

Thanks for all your answers !

And PaulQ, you're right: Wouldn't is better than couldn't...

 

[Language Hound]

And PaulQ, you're right: Wouldn't is better than couldn't...

It's not a question of wouldn't being better than couldn't;
couldn't is simply wrong here--at least in my version of English.

EDITED to add another possibility:
...if it were staring you right in the face.

 

[Hetep-Heres]

Staring right in the face sounds good too.
Thanks!