Boone PickensAP Images"One thing she was wrong on — If I didn't drink coffee or smoke cigars like my dad — those would both stunt my growth — I would be 6 feet tall."
Billionaire energy tycoon T. Boone Pickens has never tasted coffee in his life. 
The 86-year-old told Business Insider it was because his grandmother told him not to drink it.
She was actually the source of a lot of valuable advice growing up. 
"Everything she told me as far as advice was concerned pretty well played out like she said it would," Pickens told Business Insider. "You know, work hard, you get results. Always, if you tell somebody you're going to do something, always do it. Things like that."
In his book "The First Billion Is The Hardest," Pickens details the relationship he had with his grandmother. His grandmother gave him advice that has remained with him throughout his career.
"It becomes part of your personality and your life when you're taught early," he told Business Insider. 
In his book, Pickens tells a story about how he found a man's wallet while on his paper route as a young boy. He returned the wallet to its rightful owner. The man gave Pickens a dollar as reward. When he got home he told his grandmother, mother, and aunt about the dollar he received. 
"[My grandmother] made me return the dollar I got. 'You're not going to be paid to be honest. That ain't the way it's going to work,'" Pickens recalled.
"'No, no, he wants me to have it,'" he remembered telling his grandmother.
Pickens got on his bicycle and left to return the money to the man. On his way home, he got caught in a downpour.  
"I almost drowned coming back," Pickens said. "I wanted her, my aunt and mother to see me pitiful when I came back on my bicycle and feel sorry for me. None of that at all. I came in and said, 'I almost drowned when I crossed Burgess Street.'" 
His grandmother told him, "If you had gone when we told you to, you'd have been back before it rained." 
His grandmother was right.
But Pickens says she got one thing wrong.
"One thing she was wrong on — If I didn't drink coffee or smoke cigars like my dad — those would both stunt my growth — I would be 6 feet tall. I never had a cup of coffee to this day. Never tasted coffee. I never smoked a cigar either." 
"I went to her when I was 20 and I said, 'I didn't drink coffee and I never smoked a cigar either and I'm not going to be 6 feet tall," he said. "She said, 'Sonny, if you had, you might not be 5 feet tall.'" 
Pickens is 5-foot-10 and in good shape. To this day, he continues to work out with his personal trainer every morning at 6:30 a.m. 
See, grandmothers really do know best. 

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