Switzerland· hard· informal
ne pas se prendre pour la queue de la poire
“to not take oneself for the stalk of the pear”
Meaning
To think very highly of oneself
Explanation
The pear's stalk is the bit nobody wants, and this person would certainly never mistake themselves for it.
Example
Depuis sa promotion, il ne se prend pas pour la queue de la poire.
Since his promotion, he's been rather full of himself.
Origin
It first appears in a Swiss text from 1931 and follows the same pattern as older, cruder phrases that measure self-regard against something disposable.
Source