I feel the majority of libraries you will use in Haskell won't resort to errors except in two cases: One is very low-level libraries doing things like interact

I feel the majority of libraries you will use in Haskell won't resort to errors except in two cases: One is very low-level libraries doing things like interacting with C-code or raw memory. These are dangerous in all languages unless you are careful. The second is in functions that explicitly let the caller know they may fail. For example, you can write "head aList" which will cause an error if aList is empty, however if you instead write "case aList of { [] -> handleEmptyList; a:as -> handleNonEmptyList a}" then you can cleanly get around the exceptional cases. It does take discipline to use these functions and when writing in "quick and dirty" mode I do skip and use the other functions, but they should only be used carefully.