What if, say, you go to open a file in C and if you don't say what happens when the file doesn't open, then that creates some kind of error condition that gets implicitly called?"
Gee, like in Burroughs ALGOL in 1970?
Their OPEN could be called 3 ways:
If open (....) then
... // your code to do some error handling
Open (...) [error_label]
// implied goto if open fails
Open (...)
// implied abort() if open fails