What makes such phenomena as rainbows so much more wonderful is that we understand how they are created. Humans have provided natural explanations of such beauty, and the explanations themselves are a source of beauty. I became a scientist partly because I was so enamored by the physical laws that govern everything. If you are not familiar with how rainbows are formed, read up on the topic. You'll find there's a lot of beauty behind the beauty we behold in nature.