I can't count how many times I've said "this is really bad, I it is worth rewriting to fix all the issues", only to discover that there were good reasons for all the past decisions and so we end up with the same mess as before - except that now I know what it must be that way.
Not always, but very often people in the past had good reason for what they did.
Not always, but very often people in the past had good reason for what they did.