Should "Good Morning" always be used as the first greeting of the day? [closed]

Is it true that regardless of the time of the day, the first wish to a person must be Good morning? Even if I meet him in the afternoon?

Solution 1:

No it is not.

• Good morning - any time in the morning after waking up
• Good afternoon - between noon and evening
• Good evening - in the evening
• Good day - any time, but it feels old-fashioned

Good night never means "hello", always "goodbye".

There are times of day when there is no really appropriate "Good ..." -- for example, Good morning is not appropriate if you join your friends in a nightclub at 12:30 am, but neither is Good evening.

Solution 2:

Slim is entirely correct.

One occasional exception to those rules is that "Good morning" is often used ironically.

For example, if it's 4pm and I meet a coworker who looks tired, I might say "Good morning" in a joking tone, implying that he seems to have just woken up.

Or if a friend accompanied me to a late-night movie and fell asleep halfway through it, when I woke her up after the movie I might say "Good morning" as a friendly way of ribbing her for falling asleep.