"Have A Happy Shabbos"
On two occasions, I noted that the Sudilkover Rebbe wished me a "happy Shabbos" instead of "good Shabbos". While English is not his first language, I intuitively understood that he had chosen the word "happy" to express a specific idea.
When I finally asked him about his word choice, the Rebbe responded that he uses the word "happy" since it has an unmistakably positive connotation and the word "good" does not seem to mean anything as it is commonly used in American English. He then remarked,
"The most important thing on Shabbos is being b'simcha. A person must be happy!"