You must be happy when you have high salary. you can buy anything that you like. You can eating out frequently. You can buy the car that you like it very much.
However, you must remember that some day you will not receive the high salary. Perhaps your boss fired you or perhaps your company bankrupt. You cannot work again because the accident. Any reason that caused you have no job.
That is why you need to invest your money beside saving. One day you need the money to fulfill your spending. You can still buy anything that you need though you have no jobs.
You can set aside money from salary for investment. There are lot investment. Long time ago, people buy land to make money. They can use the land for farming that produce grain or cattle. They can hire the land to other people so they receive money.