I totally agree. I actually always start from scratch - sort of. I usually start with Garland, but then I strip out all html, toss the css completely, and even kill a lot of the unnecessary php. I then go into the .info file and add js, css, regions, etc. (I usually like an intro region, which is great for the home page).

Starting from scratch allows my sites to look completely fresh and new. I've gotten comments that my websites don't look "Drupally", and I think starting from nothing is why they look so different.

I hate mucking about in other people's code, especially if it was written by developers. Front end production is usually a very different skill than what most developers are used to. Also, using another theme as a base often throws confusion and wasted time into the mix when I try to get the CSS right. There is often so much cascading styling competing with each other that I'll always have to go in and tweak and retweak until it's right.

More efficient to just start over.

Tevi