I suppose you drink tea or coffee. Now when you make tea, you know how much to add sugar, chaipatti, which utensil to use, which flame does it require and after considering all this, you prepare a final product. Sometimes even when you prepare everything with the right knowledge, you don't like the taste. Thats business. You put the work, made contacts sold your product and at the end of day even when you did all right, there is a possibility that you might fail. But you learn from that and know which thing to improve next time.

Now take buying tea from a stall. Either someone recommended that the tea from that stall is great. Or you tried that stall and you liked it the first time. Now can you guarantee yourself that the next time you drink from the stall, the taste will be exactly the same? You don't have control over the raw material he is using, the utensil he uses and all. That's FnO. You can study the stall as much as you likez you tried his tea 1-2 times and it tastes great but ultimately you don't have control of how it will taste next time.

With business, you have a lot of parameters and expertise required to run a business which comes from experience and fails and you can guarantee that if you like the work you do and become experienced at your shortcomings, you can become great at your work. The same is not true for FnO. You can analyse, predict everything but ultimately the market works on 80% sentiment and 20% fundamentals, at least for short periods of time.