The smell of the exhaust from gas driven forks was always particularly obnoxious to me, I really hated it. But I like the smell of diesel exhaust, go figure.
The gas exhaust smells bad. Rotten or something. But diesel smells good, I like that diesel and diesel exhaust smell. Maybe it's because I spent a lot of time around diesel fumes and exhaust as a kid, it reminds me of good times.