This is the 5722nd most frequent Russian word.
приятным
"Pleasant" or "nice."
Adjective "приятным" modifies the noun "сюрпризом" in instrumental case, describing the nature of the surprise.
Эта встреча была очень приятным сюрпризом.
This meeting was a very pleasant surprise.
Adjective "приятным" is in instrumental case, modifying the noun "голос" to describe its auditory quality.
Её голос был приятным на слух.
Her voice was pleasant to listen to.
Adjective "приятным" is in instrumental case, describing the result or quality imparted to "day" by the stated action or activity.