The current belief that 'If you still feel that working in one Windows environment will be the same as working in any other Windows environment' indicates that you have already formed an expectation that things will remain unchanged with another Windows environment. So, in essence, you are 'not waiting for something' or 'expecting something' to change. You believe things will remain the same.
'In for a surprise' in this example means you are 'guaranteed to get' or 'go through' an unexpected happening (surprise).
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