The phrase "dull as dishwater" refers to something that is extremely boring or uninteresting. However, there are numerous antonyms that could be used to describe the opposite of this. Words like "exciting", "thrilling", "stimulating", "captivating", and "engaging" can be used to describe things that are the complete opposite of dull. Such things may be full of life, energy, and excitement, leaving one feeling refreshed, invigorated, and motivated. Rather than being tedious or monotonous, they may be defined by their vibrancy, spontaneity, and exhilaration. So, while "dull as dishwater" can be used to describe some experiences, there are plenty of other words that can be used to describe things that are far more stimulating and interesting.