Kranz was slightly anxious about his team — not that their youth or inexperience would be a detriment, but that they might feel inadequate. Just because they had been selected last didn’t mean they were the leftovers. To boost morale, Kranz as their leader wanted some insignia for his team to rally around. His wife, Marta, suggested a vest: Kranz loved the three-piece suits that were in style at the time, and she loved to sew. In 1962, she suggested she make him a white vest to wear at his console...
Kranz wore his first white vest on Gemini 4, and it was an immediate hit with his team. He also became lead flight controller during that mission. During the first shift, Kraft turned to Kranz, said “you’re in charge,” and walked out.
But that's only the beginning. Mrs. Kranz made many vests, in different colors, patterns, and fabrics, each for a different mission occasion. Link -via a comment at Metafilter