1."Wishingyouhappinesseveryday"expressesacontinuousstateofhappiness.2."Mayyoubehappyeveryday"isablessingforongoinghappiness.Bothsentencesconveythesamesentimentofwishingsomeonehappiness,buttheyhaveaslightlydifferentnuance.Thefirstisadeclarationofthestateyouwishforthem,whilethesecondisablessingorwishfortheirhappiness.