Throughout Karasuno's matches at Nationals in the anime "Haikyuu!!", there are several emotional highs and lows that the team experiences. Some of the emotional highs include moments of intense determination, teamwork, and exhilaration when they score important points or make a comeback. On the other hand, the emotional lows consist of moments of self-doubt, frustration, and despair when they face tough opponents or fall behind in the game. Overall, the emotional rollercoaster of highs and lows in Karasuno's matches at Nationals makes for a gripping and engaging storyline.