The worst smell HAS to be a burning seed. I love high grade and it's extremely rare that you put your kush in the grinder and find hella seeds in your "ingredients." This reason alone makes me despise reggie weed; that's the only time I smell burning seeds.
When I first started smoking, I couldn't tell when a seed was burning or if it was just the weed smoke until someone pointed it out. Ugh, fuckin seed.. It wasn't until I started smoking habitually that I started craving the taste of high grade and distinguishing burning seeds from bud. And now it all makes sense why everyone hated the smell - it's fucking disgusting!
You could never front and say your smokin' strong and then everyone around smells seeds. Everyone knows seeds are usually found in reggie!