The grass is always greener on the other hill.
Almost all people see that the grass is greener on the other hill. They never feel satisfied with what they've already got.
get into one's blood
It's astoundingly funny that many harmful things usually get into our blood.
I'm really bored stiff with his sitting there doing nothing but beefing.
champ at the bit
Let's shake the leg. The kids are champing at the bit.
bow and scrape
From the way she's bowing and scraping in front of the boss, you'll know what sort of person she is.
Don't take what he says so seriously. He's always going gaga.
go back on one's words
We cannot account on him. He always goes back on his words.
beat one's gums
Who would enjoy sitting there listening to your beating your gums?
bite the hand that feeds one
Don't you know she's the one that would bite the hand that feeds her?
not have the heart to do
If I were you, I wouldn't have the heart to leave the kids at home uncared for.
an eager beaver
He's an eager beaver, never staying idle.
judge a book by its cover
You can't judge a book by its cover.