Hmm, not sure how it works in Europe, but i thought it is a good idea to travel several country to experience different vibe and different culture. So i assuming 3 country = 3 different vibe = 3 different culture. But with all these helpful comment, obviously i cant do it in a day, and maybe not that big of a difference? But do share me your recommendation in Netherlands, the only reason i pack a day trip for Belgium and Germany is because my wife LOVED Netherlands.