Now I am often accused of being a goody goody but if the limit is 40 then why not just stick to 40 rather than deciding that in your opinion 50 is fine. Never quite understood why some people need to go faster than the displayed limits, but as I say I am often called a rule follower in life rather than breaker. I honestly can't recall exceeding the speed limit in any of the decades I have been on the roads, have just never seen why I would need to.
I don't need to break the speed limit. Similarly, I don't need to obey it. It just happens that the former is breaking the law.
When you go from a 30 limit in to a 40 limit, why don't you stay at 30? You don't need to do 40. That extra 10 mph isn't going to get you there a great deal sooner, so why not stay at 30?
I have no reason for breaking the speed limit when I do, other than I'm driving to the conditions of the road rather than an arbitrary number printed on a sign. If you think that number will keep you safe then great, good for you. Having said this, I fully accept my punishment for when I get caught and at no point will I argue against the punishment. I broke the law fair and square.