1. Not washing your hands after you pee.
Have you ever heard the line that "urine is sterile" so there's no need to wash up. Um, sorry, you need to wash your hands. Sterile urine aside, there's still the business of wiping, flushing, and touching door handles--all of which could lead to cross contamination that can make you sick.
2. Eating food samples at grocery stores.
For the same reason you wouldn't lick a stranger's hand, it's best not to dive into the freebie bowl of chips at the supermarket. Ask yourself: "Would I open up a bag of chips and share it, communally, with 50 people on the street right now?" Probably not.
3. Coughing into your hand.
Maybe it's just me, but everywhere I'm looking these days people are coughing into their hands--instead of the inside of their elbow. If you tend to do this, try to retrain yourself to cover your cough with your arm and not your hands--it's polite and it also helps protect others with weaker immune systems from catching any bug you've got.
4. Rubbing your eyes--ever.
After a fairly icky eye infection years ago, a doctor told me this: Think of your eyes as sacred and untouchable, and retrain yourself not to touch them with your fingers (no rubbing or messing with your eye makeup until you've washed them first). The second you touch a dirty hand to your eye, you're introducing all kinds of harmful bacteria and viruses, which can lead to annoying and even serious infections.
5. Letting your dog lick your hands then not washing them.
Guys, I'm a dog lover, but when my golden retriever licks my hands, I go wash them. Yes, it gets tedious to do this (because she's always giving me kisses), but it needs to be done. I will remind you that dogs and cats get into unsavory things (I'll just be blunt: mine likes cat poop). More: Our pets might also be passing along dangerous staph bacteria, such as MRSA, to us.