Who said "You never know what you're capable of until you try."?

This quote is attributed to Frank Costanza.

You never know what you're capable of until you try. - Frank Costanza

"You never know what you're capable of until you try."

Frank Costanza Perseverance

"These pretzels are making me thirsty."

"I'm out there, Jerry, and I'm loving every minute of it."

"Giddy up!"

"The sea was angry that day, my friend."

"Perseverance is the key to success."

"Don't give up on what you believe in."

"I've been through worse."

"You learn to live with the pain."