Hey, Mister Germaphobe, we see you on the subway, packed together with everyone else during rush hour, and you refuse to hold on.

You won’t touch the pole, or loop your hand through one of those overhead tether things. You’re standing there “surfing” with your arms crossed on your chest. Why? Because you’re afraid every surface you touch is covered in bacteria and viruses.

And, look, you’re not totally wrong. According to a 2016 study, public transportation is host to hundreds of bacterial colony-forming units—per square inch. But consider this: when the train brakes unexpectedly and you topple over into a crowd of strangers, won’t that expose you to even more germs?

If you’re germaphobic, it’s easy become so obsessive that you end up missing the point. You only touch the elevator buttons with your knuckle. But isn’t that the same knuckle you use to rub your eyes? You wipe down the tray table on the airplane… but then you walk to the airplane bathroom in your socks. You imagine germs on certain surfaces, but ignore them on others.

You need a reality check. We read the studies and talked to one of the world’s premier germ experts to get a read on what you should be avoiding, and what doesn’t matter.

Know your infectious surfaces

What’s worse? The subway pole or the weights at the gym?

Yes, public transit is germy. But if you exclude New York City (sorry, Pizza Rat), you're looking at a relatively low bacterial count of mere hundreds of colony-forming unitsper square inch. (Those are "CFUs" to germaphobes in the know.) Some taxis rank in the thousands. But gym equipment has over a million CFUs per square inch, with exercise bikes being the dirtiest, followed by treadmills, followed by free weights.

The good news, if your gym asks you to wipe down your equipment after use, that essentially takes care of the problem.

“People have found MRSA and cold virus on gym handles,” says Dr. Charles Gerba, a microbiologist at the University of Arizona, “but these surfaces are clean enough if your gym encourages you to use disinfectant and paper towels. Culturally, this seems to have come in, and you only need a few people doing it to break the cycle.”

Rule of thumb: how much is it touched?

What makes some surfaces germier than others? The frequency with which they’re handled.

That means things like light switches (touched a couple times a day) are pristine compared to the key pad on the vending machine (touched constantly). In the elevator, the “lobby” button is far germier than the button for any other floor. At the office, the conference room might see a lot of traffic, but it’s far cleaner than… the break room.

At the University of Arizona, Dr. Gerba has studied the way viruses and bacteria move around in office hangouts. “The first thing to get contaminated is the coffee pot handle,” he says.

So what should you do? “Be the first one to get to work,” he suggests. “Or maybe go to Starbucks.”

You can stop using a paper towel to open the bathroom door

You know you’ve done this: washed your hands in the men’s room, dried them with a paper towel, then used the towel to open the bathroom door so your palm won’t touch the handle. You can stop.

Yes, the bathroom door handles are one of the most frequently touched surfaces in your environment. But most people are touching the exit handle with cleanhands.

“Door handles in restrooms don’t seem to be an issue,” says Gerba. “And certainly the entrance handle is dirtier than the exit handle.”

“Sanitizing” doesnt always help

In most instances, washing your hands puts you in the clear. “If you’re out in public, when you come back home either wash your hands or use a hand sanitizer,” says Gerba. “That seems to alleviate the problem.”

One exception: there’s a place in your home germs love to colonize. It’s called your kitchen sponge.

One of Gerba's studies found kitchen sponges to have around 10 million bacteria per square inch. And these are the bad ones. Bacteria that ride in on raw food—such as salmonella.

If you've heard that microwaving your sponge sterilizes it, think again. A study out last month suggests that microwaving only kills the weak bacteria, leaving the stronger, more deadly strains plenty of room to multiply.

Your phone’s ick factor is a mystery

You know those gadgets that are supposed to sterilize your phone with ultraviolet light? They’re playing on your fear.

“Touch screens are hard to evaluate because you put things on and take them off so rapidly,” says Gerba. “You might swipe on 100 viruses and then take 50 off.” What does that mean in practice? “We’ve studied people’s cell phones, and they’re usually not that bad.”

So before you drop cash on an phone sterilizing pod, maybe just wash your hands.

You are tracking poop everywhere

If you have a friend who makes you take off your shoes every time you visit… he's onto something.

Gerba’s team tested shoes after they’d been worn for a month, and 93% of the soles had fecal matter on them—plus, roughly a quarter had E. coli. “We were surprised to have found so much,” he says. “Apparently they survive longer in the grooves of the soles.”

You track all that disgusting stuff from the sidewalks of your city into your home. (In fact, the first couple steps by the entrance are the dirtiest.) So shuck your shoes, and watch what you do with them out in public. “I no longer put my feet up on my desk,” says Gerba.

Exposure doesn’t equal immunity. (At least not for diarrhea)

You’ve probably heard that some exposure to germs makes you stronger. And, yes, that’s true in some cases. But it’s not a good argument against washing your hands.

Consider certain viruses, like norovirus—the one that can send an entire cruise ship’s worth of passengers running for the restrooms. “There’s no long-term immunity for norovirus,” says Gerba. “You can get it as many times as you want.’’

So if you want to get it zero times, consider a squirt of Purell.

Surprisingly okay: the toilet seat

Finally, if you’re going to single out germy surfaces, there’s one that gets a bad rap.

“Toilet seats are incredibly clean,” says Gerba. “There’s usually more fecal matter on a cutting board in a home. It would be safer to make a sandwich on a toilet seat.”

The reason, he says, is that people tend to treat toilet seats with a lot of germ sensitivity. They wipe them down, or use those paper shields. Consequently, the seats end up cleaner than you’d think.

“We’ve studied homes, schools and offices, and one of the cleanest things is the surface of the toilet seat,” says Gerba. “If someone dares you to lick something in a public restroom, pick the toilet seat."