Was your holiday exciting? -Yes, it was the most exciting holiday I've ever had
Was your car powerful? -Yes, this car was the most powerful I've ever had
Was the coffee strong? -Yes, it was the strongest coffee I have ever drunk (I've ever had тоже можно)
Was the meal good? -Yes, this meal was the best I've ever had
Was your journey comfortable? -Yes, it was the most comfortable journey I have ever had
Was the soup cold? -Yes, it was the coldest soup I've ever had (хотя можно пофантазировать, и написать например it was the coldest soup among other foods)
Was the lesson difficult? -Yes, it was the most difficult lesson I've ever had (или опять же можно пофантазировать, и например написать The most difficult lesson in this month, или for the last week)