After a decade of hosting "Mad Money," Jim Cramer has interviewed countless CEOs. But there was one CEO that called him that stopped him dead in his tracks and shocked him more than any other CEO ever has.

The "Mad Money" host was left with a deer in the headlights look on his face, when Apple CEO Tim Cook called to wish Cramer a happy 10th anniversary. Of course Cramer took the opportunity to educate Cramerica by questioning Cook on the potential downstream benefits of the new Apple Watch.

Cramer elaborated by saying that Apple is not only just about fun technology gadgets, it is also the health company and credit card company of the future. Those are the two areas of growth that Cramer sees Apple gaining the most strength in currently.

Cook said that the watch's impact on health has been so strong that within the first 24 hours of announcing the research kit some 11,000 people signed up for a study in cardiovascular disease through Stanford University. Cook said it would typically have taken 50 medical centers an entire year to sign up that many people.

"Research kit is an absolute gamechanger," Cook said.

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Cramer also believes that Apple Pay will be a major gamechanger in the retail sector. Those customers will start to demand it from retailers, and they will need to convert to Apple Pay.

"I totally think you're right. You said last year that it would take the country by storm, and it is doing it. We've already got 700,000 locations accepting Apple Pay," Cook noted.

The mantra that Cramer has been encouraging investors for years to abide by is to own Apple, don't trade it. He still considers it to be a cheap stock with a strong balance sheet. Does Cook also agree with this mantra to trade his stock?

"For people that have owned the stock for 10 years, our stock price 10 years ago when you started 'Mad Money' was less than $6 on a split adjusted bases. So you can bet those people are extremely happy right now," he answered.

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