Idioms and sayings in Turkish providing this meaning may be:
- Sen bir de ona sor! (Ask him/her before envying about his/her life/job/etc.)
- Dışı eli yakar içi beni yakar. (Literally means: The outside (of his/her life/job/etc.) burns others, the inside burns him/her. I think this needs no further explanation. :))
- Göründüğü gibi değil. (It's not the way it seems.)
- Kazın ayağı öyle değil. (Literally: That's not how the goose's foot is. This idiom has been derived from a story of the famous Turkish folkloric figure Nasreddin Hodja. You may want to read this: http://en.wikipedia.org/wiki/Nasreddin. Also you can find the original story by searching the idiom on the internet.)
- O kadar kolay mı? (Is that so easy? (this question implies it's not.))
There are others already suggested by other linguists here and there are probably more of them. Turkish is rich with its sayings and idioms.