It does not work that way at all - nowhere in Europe.
You have ranges, say from 0 to 100 you pay 10%, then for the amount above 100 up to 200, you pay 20%, then for the amount above 200 to 300 you pay 30% and so on (the numbers are all made up).
So when you get a raise from 100 to 150, you pay 10% on 100 (10) and 20% on 50 (10), so a total of 20. You get a net 150-20 = 130.
If it was the way it was described it would be insane.
There are also cases where the tax is flat and the same no matter the amount (usually not for salaried people)
You have ranges, say from 0 to 100 you pay 10%, then for the amount above 100 up to 200, you pay 20%, then for the amount above 200 to 300 you pay 30% and so on (the numbers are all made up).
So when you get a raise from 100 to 150, you pay 10% on 100 (10) and 20% on 50 (10), so a total of 20. You get a net 150-20 = 130.
If it was the way it was described it would be insane.
There are also cases where the tax is flat and the same no matter the amount (usually not for salaried people)