When Mitt Romney introduces himself to voters, he has a peculiar habit of guessing their age or nationality, often incorrectly. (A regular query: “Are you French Canadian?”)…

The results can be awkward. “Daughter?” he asked a woman sitting with a man and two younger girls at the diner in Tilton, N.H., on Friday morning. Her face turned a shade of red. “Wife.”

Oh, Mr. Romney said. “It was a compliment, I guess,” said the woman, Janelle Batchelder, 31. “At the same time, it was possibly an insult.”…

Mr. Romney likes to congratulate people. For what, exactly, is not always clear.