At the drop of a hat: If you do something at the drop of a hat, you do it immediately without stopping to think about it. Immediately; instantly< (ES: de inmediato)

Anna was always ready to go fishing at the drop of a hat.

Hold your head up: If you hold your head up high, you are proud and confident of your actions, creation or product. (ES: mantener la cabeza alta)

– We lost again. We’re the worst team ever!
– Keep your head up, Alex. you still have the whole season.