Why do you never receive the full amount you negotiated during the job interview? Once your gross earnings are defined, the law mandates the deduction of certain percentages from that pool before you receive the payment. These items primarily go into public coffers (funds and the budget).
The most solid deduction and the largest hit to gross earnings in absolute terms is intended for the days when you will no longer be able to work. It is paid to the relevant PIO fund. Pension deductions are a fixed percentage of your gross earnings.
Tax on your earnings that finances the administration (schools, infrastructure of your place of residence). This is a variable item — the rate depends on the level of your income and legally determined local reliefs.
In addition to tax and pension, fixed percentages are deducted from gross earnings for insurance in case of unemployment and health protection, thus ensuring the social security of the worker.
In addition to legally mandatory pension payments and taxes, your net salary can be burdened by specific suspensions realized during payment (effectively deductions from your Net amount):