smells

Some good smells include:

fresh grass

washed clothing

newly born babies

air mattresses

small filing cabinets

dense magnets

leftover Olive Garden in a styrofoam container

books made of polymer 

nylon

bbqs

the nhl

leather sporting equipment

receipts from items purchased that passed the test of longevity

anything that is designed and printed nicely

cedar

any volkswagen manufactured between the years of 1983 and 1992

any purse

all packages received from amazon.com

electricity

those soft sticky eyeballs that you get in a quarter-machine at a 50's-themed diner

some bad smells include:

your own burning flesh

hair of any kind

people who have been working out for an extended period of time

plastic spider rings that you get at halloween

a woman's clothing who isn't your mother when you are 7 years old

shoes that you've worn every day for the past 6 months

fried leftover potatoes

burnt corn

ridiculously obese people who can't possibly clean their entire body

your arm after it's been in a cast for any period of time

french public transportation

cavity breath

mold of any sort that looks like it might be powdery or could become so at any point in time

any volkswagen produced between the years of 1992 and 1999 that is owned by a student

a season of soccer without the smell of wet leaves

your old house

cat shit.