These are probably the most used two words in our day-to-day conversations. We normally use superlative degrees all the time to emphasize something strongly. That being the case why we don't.

Good evening is used from 4 p. m. Till even night. Good night as noted by yourself means to have a good night's sleep, so good evening is used. However, most of my colleagues will keep saying have a good night to each other, so it's better for me to do the same thing. Also, sometimes when it feels really weird or awkward to say, i will say have a.

Also, sometimes when it feels really weird or awkward to say, i will say have a.