Comma after greeting and closing

[mrmvp]

In formal messages, sometimes greetings and closings are followed by a comma, and sometimes they are not. Should I add a comma after the greeting and the closing?

For examples,

Dear John,
Best regards,
Best,

 

[emsr2d2]

In formal messages, sometimes greetings and closings are followed by a comma, and sometimes they are not. Should I add a comma after the greeting and the closing in the following examples?

For examples,

Dear John,
Best regards,
Best,

All of those should be followed by a comma. Greetings/closings that should be followed by a full stop are things like "Hello", "Hi, everyone", "See you soon" and "Bye for now".

Note that even when you're about to give more than one example, we always say "For example", never "For examples". I removed those two words from your post anyway as it was neater to incorporate the introduction of your own examples in the preceding sentence.