I know that they will rotten eventually, if somebody doesn't use a rake soon enough, yet they are so beautiful to look at and they cheer me up everytime, especially when the weather is rainy - they're the only colourful bits of autumn! ;-)
You are right, yellow leaves are like sun on a sunless day :)
The colours are amazing. I wish our leaves would look like that in autumn.
They really are beautiful, but of course the trees look now quite sad without them