لماذا نقول Have a ......?
 

I n conversation the imperative is often used to express a wish
Have a good holiday .
E njoy yourself and come back quite well again.
A Comprehensive English Grammar

كل عام وانتم بخير

انا مع حضرتك فى الراى اننا نحذف may ولكن هنا لا يوجد فاعل
May God help you. تصبح God help you
اما هنا لا يوجد فاعل مثل Open the door.

Have a nice day. and Have a good day.; Have a nice one.; Have a good one.
Cliché an expression said when parting or saying good-bye. (This is now quite hackneyed, and many people are annoyed by it.) Clerk: Thank you. Tom: Thank you. Clerk: Have a nice day. Bob: See you, man! John: Bye, Bob. Have a good one!

Have a nice day. and Have a good day.; Have a nice one.; Have a good one. Cliché an expression said when parting or saying good-bye. (This is now quite hackneyed, and many people are annoyed by it.) Clerk: Thank you. Tom: Thank you. Clerk: Have a nice day. Bob: See you, man! John: Bye, Bob. Have a good one!

الحل imperative

yes , that's right