The level of politeness in a salutation can vary based on the relationship and situation. In a business email, 'Dear Sir or Madam' is a polite salutation.
Pro Tip 2/3
Cultural Sensitivity
Different cultures have unique salutations; it's important to be aware to avoid misunderstandings. In Japan, a bow can be a respectful salutation.
Pro Tip 3/3
Non-verbal Greetings
Salutations aren't always spoken; nods and handshakes are non-verbal examples. He gave a nod as a silent salutation when he entered the room.