Maccarone
To have a heart the size of a pea means you're a cold, selfish jerk who can't feel anything but your own needs.
My brother has a heart the size of a pea. He left me in the rain with no umbrella.
My ex had a heart the size of a pea. She took my money and left me with a broken phone.
My mom has a heart the size of a pea. She forgot my birthday and my college application.