I saw your thread title and was immediately taken back to a memory of my daughter when she was about 3 years old. (She's 16 now)
One day, when she was feeling particularly irritated at me, as 3-year olds often are at their mothers, she said "Mom, you are pushin on my last nerve!" I just love how little kids can mix three metaphors.
1) Pushin it!
2) Last straw!
3) Getting on my nerves!
Thanks for bringing back that memory for me today. It surely put a smile on my face.
L