Now when you send an object into a library function you don't have the slightest idea what the function will do to your object There are more languages then C#

Now when you send an object into a library function you don't have the slightest idea what the function will do to your object There are more languages then C# which tend to have these problems, and for all of them these problems can be avoided in a number of ways merely by applying the typical good practices and well known design patterns. For instance just giving your functions proper names (examples 1. GetLongestString 2. StoreReferencesToAllStrings (still hacky, not sure if there are proper usecases for that?) 3. RemoveDuplicates 4. InstallList or so) and making sure functions do One Thing only will get you a long way in preventing problems. Not saying it is easy, but I've been using C# for at least 5 years and don't really recall problems with it. Did have problems with weak event handlers disappearing due to gc but after learning it it didn't happen again.