haha yeah the return values of bang methods in ruby are a bad surprise indeed.. this also leads to the fact that you can not safely chain them. I mean, you can chain them if they always modify something and return something but once when they don’t… BOOM.
One of the very unintuitive parts. I hope they change it in 3.0 but guess they won’t 
It’s actually intentional. It allows for code of this style (borrow from Perl):
>> s = "cows"
=> "cows"
>> if s.sub!(/s\z/, "")
>> puts "You now have a #{s}"
>> end
You now have a cow
=> nil
That again brings up 'Wouldn’t it be better to return true/false instead of a potentially usable value from death?`. 
Since it ‘sometimes’ returns self it seems like you could do myArray.uniq!.sort, but that will die at times, seemingly very randomly too. ^.^
With proper typing that would be impossible, either you’d always have to return self, so .sort would always work, or you’d have to return some variant of self | nil, meaning you’d have to match on it or default it out or so. true | false makes so much more sense in that context.
