Super duper is a jokey, childish way of saying something is better than 'super'. It would only be said by children or to children, or with family and friends in an informal way. It certainly wouldn't be an assessment of something in a serious business environment. "How is the ice cream?" "It's super duper!" Snap out of it would be said to someone who is in a certain negative mental state to instruct them to change that state. So if someone were daydreaming, they could be told to 'snap out of it' to mean that they should stop dreaming and return to normal. It could also be said to someone who was depressed and unhappy and cannot seem to stop being so. It's an instruction to them to try and bring themselves back to normal as soon as possible and stop with negative thinking that is creating the problem. If someone had a real problem with depression or similar mental condition, being told to snap out of it would not help. The person saying it could be perceived as an unsympathetic person who thinks the problem can be fixed by a conscious choice to change which may not be possible.

Hi Fonso, agreed, super duper is a fun way of saying something is great. As for snap out of it, I wouldn't say it always pertains to a negative state, it is used to pull them out of their current state, but sometimes people daydream to escape their current state which is more boring.