Depends on what you mean by "important." You noted yourself that "life got easier" once the language you used introduced generics.

Generics can drastically reduce the time required to implement features because less time is spent on re-implementing (nearly) identical algorithms for different data structures and more on simply using them to write something that works.

The cost paid for this is usually in the form of minor efficiency hits because data-specific efficiencies aren't exploited.

Also, consider me complaining about C's lack of generics. It is in fact the primary reason I prefer C++. If C had robust generics with reasonable syntax I'd strongly consider using it instead of C++.