Hidden charges are just a builder's final EMI

Why do builders still pull the hidden charges stunt, especially for projects on Golf Course Extension? My friend just took possession of an Emaar flat there, and the final bill had like 3-4 lakhs extra for 'miscellaneous' stuff not in the original agreement. M3M is also notorious for this, I hear. Plus, the construction quality on some new Godrej projects feels rushed. Are we just expected to accept this? What's been your experience with DLF or Sobha on this front? Did you fight it?