Often at the beginning, people make the mistake of being convinced that the standard is sufficient. However, many things are, for me, for example, a must-have. Blinds in the south/western living rooms, for example, would not be for me. You mostly have them down during the day in summer. With venetian blinds, you have protection from direct sunlight and still get a lot of light. But it does cost quite a surcharge. If you have a wooden staircase and later find out that you really like oak parquet, you will want the staircase to match. And the standard shower cabin is not as nice as the walk-in tiled one with rain shower head and thermostat.
Believe me, almost every builder goes through that...