In China , we have a saying: everyone is short in dogs' eyes.

It is used when someone look down on u.

Mine is "as scarce as hen's teeth" and I'm guessing that most youngsters won't understand this one at all!

On the same theme, we sometimes say that we feel like 'Death warmed up'.  It sounds rather over-the-top, when you think about it.

In Australia (and I think NZ as well), we have the phrase "crook as a chook". It's the exact same meaning as "sick as a dog", just that we use "crook" for sick and "chook" for chicken.