After a 20% raise, spending almost always rises 20%. The car improves, the apartment improves, the vacations improve, and two years later the sense of comfort is precisely what it was before, with one important difference: the standard of living now costs more to keep.
That is the double cost. Not only did you not save the raise: you have raised the wealth you will need to be independent, because that target is calculated from your annual spending. Every $100 of permanent monthly spending adds roughly $30,000 to the number.
The antidote is not austerity but pre-allocation: deciding how the next raise gets split before it arrives, say half to automatic saving and half to living better. Chosen in advance, it is a decision. Chosen afterwards, your habits already decided it for you.