Miss Manners: Is husband’s small business sending out uncouth greeting cards?

Miss Manners: Is using a courtesy title in a friendly business correspondence unnecessarily formal?

DEAR MISS MANNERS: I have discovered that my husband’s small business has been sending out birthday/anniversary cards addressed to clients by their first names (i.e. Joe Smith). I believe that the envelopes should be addressed using a title (Mr. Joe Smith). I have been informed by my husband, and his young receptionist, that using the title is too formal and omitting it is friendlier.

Miss Manners: Is husband’s small business sending out uncouth greeting cards?

She's concerned with how the cards are addressed. Miss Manners is concerned with maintaining a business-like relationship.