“Happy Thanksgiving. Have a blessed day.” Here happy Thanksgiving is the greeting and, have a blessed day is the wish. Greetings are formal expressions that are generally used while welcoming someone. But on the other wish is a desire for something marvelous or amazing to happen. So, when greetings are used, you express your good feelings towards that individual, and when you wish you hope for something. Similarly, in the expression above, “Happy Thanksgiving” shows your feelings, and later in the phrase, you desired something.