It´s not because you like to create new worlds objects or anything else wich came into your mind and imagination.
You don´t feel proud if someone likes your map and tell you so.
No the real reason is pain!
Remember the endless hours you try to create the map you want.
Remember the endles hours of bugfixing.
And once done you release the map and wait for realy bad reviews.
So let´s start a small contest about the worst reviews you got from the community.
Here are mine:
"Why does everyone love this map so much?...but it's so bland and ugly"
"man, all i can say is it stinks."
"in my opinion, MAF=Puke!Two Thumbs Down!"
"sucks for me"
"This thing screwed up my game
"
but I can only say, that I love to feel the feeling of endless work - and see it work 
you 'do all the hard work' 
