As a child, he enjoyed constructing thing things from pipes, much to the disgust of his mother Rosa. His other hobby, probably more supported by her, was crafts.
When in his teenage years, Jules took 'Caesar' as his second name. For the rest of his life, he was ashamed of that choice.
Just like for many, for Stein Rolls Royce was the epitome of luxury. As a hard working teenager, he dreamt of having one and looked up to the day when he can buy it. In his eyes, this would validate the fact that he "has made it". In his twenties, that moment has come - the used Rolls Royce was bought from leader of one of the bands signed to MCA. The price was $1,800.
For a brand new Rolls Royce, the businessman had to wait until he has more money to spare. He traveled to England to buy it and leveraged the expenses by buying few more (which gave him a discount), exporting them to the USA and selling for a profit. In other words, he was making money even during financing his childhood dream!
In the early business years, Stein played risky by refusing to pay off the mafia. As a result, he was on their crosshair and his life could end at any time - in such cases, it was a common practice to kidnap, torture, demand ransom and sometimes even kill the man. After getting informed by his friend and business partner James Petrillo that he is about to be kidnapped soon, he went to the insurance company and forged a deal. The terms were that if he is kidnapped, $75,000 will be paid to cover for ransom. Fortunately, it wasn't necessary.
When he was living in Deer Park (a small Illinois greenery village with lake access), he could materialize another of his passions - a love for motorboats. Besides living in a green and quiet place, another of the location's many advantages was that he could travel to work by a motorboat every day. He even got a custom one with airplane engines built for him. Bursting at absurdly high speeds on the water when someone can't swim is a gamble though, and so one of Jules' trips ended with him having to be rescued. Afterwards, he decided to sell his boat to Guy Lombardo and never came back to the hobby.
Jules, his wife and her multiple family members have a grave at the Forest Lawn Memorial Park. As Jules and Mary Pickford (early cinema's most popular female actor) were great friends, they organized it so that their graves will be next to each other.
Stein was very enthusiastic about Bette Davis' Hollywood Canteen (Wiki) - a place for military men to eat free of charge, sometimes serviced by famous actresses and actors.
Together with his wife, Jules collected a lot of staggering furniture for his office in Los Angeles. The problem was that there were a lot of bookshelves in them and leaving them empty would look terrible, so in one major initiative he bought a them in bulk to fill those shelves. He got a little bit carried away with the amount though and as a result they had tens of thousands too many.
Always having a keen eye for business opportunities, he once secretly invested Guy Lombardo's money. Jules only told him once he made $1 million profit from it, giving most (if not all) to Lombardo.
Playing violin was how making money started for the businessman. He quickly abandoned it to instead manage musicians, but never forgot how to play the instrument. During the Barney Balaban parties, he often grabbed the violin and played alongside hired musicians to entertain the crowd.
Lew Wasserman was the main force that pushed MCA into the world of politics, but Jules Stein made some friends as well. The most prominent was with the Kennedys and there Doris Stein also played a big role. She cultivated a friendship with Jackie Kennedy. At the time, the latter was leading White House Restoration Project (information and gallery here). Doris especially engaged in the campaign and became one of the most generous contributors - the fact acknowledged by Jackie in personal correspondence between the two.
Every morning, Jules was reading five different newspapers to catch up with what is going on. He continued that routine deep into his retirement days.
Waterpik's (Amazon) creator Gene Rouse contacted Jules Stein back when his revolutionary tool was an eccentric prototype that nobody wanted to finance. As a last resort, he started forcing models on rich unknown businessmen in hopes of them finding out how great this tool is. One of those people was Jules, who took it only out of courtesy and after being unable to properly set the tool up at home, quickly gave up on it. Waterpik soon made fortune and for the rest of his life, Stein considered him ignoring it the biggest financial loss of his life.
Stein's political views were very conservative for the standards back in the day (which means they are ultra-conservative by today's mainstream perception). One of the ways they were manifested was with his hatred toward communists - back in the sixties, the U.S. government was doing a witch-hunt in its ranks and extended it towards the entertainment business. While Stein never personally engaged in it, in private conversations he was often bringing up the topic and a lot of cursing was involved.
Jews in Hollywood were always teamed up and having their inner circle. They tried (and still do) to use the influence and the money they got to help with Israel's policies, battle anti-semitism etc. When new and influential Jews entered the territory, the natural way of things was to bring them to the inner circles and expect financial contributions for those causes. Stein didn't feel much solidarity for it, rejected the pressure and resented the people who made it.
In similar tone, he also wasn't religious, often saying that his sister is going to the synagogue for him.
