착한 토끼가 무서운 호랑이 만났을 때 하는 말 아닐까요? 나에게는 그런 말 하는 사람이 없어서 잘 모르겠지만요.

안녕하세요 is the most common greeting in Korean, meaning "How are you?" or "Hello / Hi!" depending on the situation. Between close friends or talking to someone much younger, one would use 잘 있었어?, 잘 지내?, or just 안녕!. In all other situations, you can safely use 안녕하세요?

Do you mean "안녕하세요"? It's basically a formal way of greeting someone :)