"Alfred Hitchcock Presents" Crackpot (1957)

Mr. and Mrs. Loomis are two newlyweds who have recently endured a family tragedy and are now having bad luck on their honeymoon. Their car has a flat tire -- and so does the spare. A stranger named Mr. Moon passes by and fixes the tire. But this Good Samaritan proves to be a crackpot. Mr. Loomis trips and falls onto Moon, dirtying his white suit. The man becomes enraged and threatens to kill him, before driving off. Later, the couple arrive at their hotel. And they realize their bad luck has gotten worse when the crackpot is in the suite right next to theirs.