10 Signs You’re a Terrible Traveler

You Have an Expired Passport and You Don't Even Know It

Some countries require that your passport be valid for at least six months after the completion of your trip just in order to enter. You may think you're in the clear if your passport expires in 2014, but if you've got a trip planned for November 2013, you'd better get it renewed before then. Always research entry requirements, including visas and vaccines, and be sure your passport is up-to-date. (If you find out the night before that your passport is expired, read this simple solution to a last-minute passport snafu to learn what you can do to save your trip.)

Your Bags are Overweight (and You're Surprised)

If you're at the counter frantically repacking your checked bags to get under your airline's weight limit, you might be a terrible traveler. Invest in a luggage scale (or a bag with a built-in weighing system, like the Delsey Helium Ultimate 25-Inch Expandable Spinner Trolley suitcase) and never be socked with an overweight fee again. Always double-check your airline's weight allowances and make sure the limits apply to connections, especially if you're going from an international to a domestic flight.

You Haven't Done Your Research

Will things be open this time of year? What currency does your destination use? What language is spoken there? If you don't know (and you don't care), you might not be the greatest traveler. There's a difference between being spontaneous and adventurous and being foolishly unprepared—the former leads to exciting stories and fun possibilities, and the latter leaves you in tears and stranded without a hotel during a major festival.

You're Cutting It Too Close

Years ago, maybe you could have rolled into the airport a half hour before takeoff, but not these days. Always leave a little bit earlier than you think you need to for the airport, train station, or bus stop—you never know if security or check-in lines will be long, or if you'll need extra time due to getting lost, roadwork, etc. Better to kill a few extra minutes at the gate than to miss your transportation.

You Don't Know the Carry-on Rules

The TSA may overlook knives and other weapons on a fairly regular basis, but they'll always find that 4-oz. bottle of shampoo you've stashed in your carry-on. Moral of the story: Know your 3-1-1 rules. Triggering a search of your carry-on bag really clogs up the line behind you.

You Spend All Your Time On The Computer

"Joe Schmo has checked in at a deserted beach (with Wi-Fi!)." "Joe Schmo is living the dream in paradise." "Joe Schmo has Instagrammed 500 new pictures." When you see hundreds of real-time social-media updates from the same person on your feeds, don't you wonder if he's really making the most out of his trip? Don't view your vacation from behind a screen. Uploading pictures and editing your Facebook status can wait until you get back, so put down the smartphone and step away from the computer!

You Don't Check In Online

Did your flight time change? If you didn't check in online, you might not know. Waiting to check in at the airport also makes you more likely to be bumped if the flight's full—or even worse, stuck in the dreaded middle seat of the last row. If you want to snag the best seats and get updates on your trip, check in online as soon as you're allowed to. You don't need to be near a printer, either. Many airlines let you check in and display your boarding pass on your smartphone, and most airports offer kiosks (usually with much shorter lines) so you can print your pass when you arrive at the airport.

You Didn't Make a Packing List

Don't be the traveler begging the front desk to borrow a power converter or the guy who doesn't know how to reach an English-speaking doctor to prescribe the medicine he forgot. Consult this ultimate packing list, use an app, or simply make your own checklist. You'll be able to pack everything you need (and nothing more) for your trip, even at a moment's notice.

You Brought Too Many Carry-ons

If you're trying to circumvent the rules by bringing on an oversized suitcase plus multiple personal items, please stop. When you're blocking the aisle, trying to shove your laptop under the seat or filling your entire row's overhead compartment with your giant puffy jacket, full-sized pillow, and yoga mat, just know that everyone else on the plane hates you, you terrible traveler.

You Yell At People

The ultimate sign that you're a terrible traveler is yelling at or otherwise being rude to travel staff or fellow tourists. Don't take out your anger about a canceled flight on a helpless gate agent who is just trying to do his or her job. Likewise, it's not your fellow passenger's fault that you're stuck in a middle seat, so stop passive-aggressively sighing and trying to invade her personal space. By all means, stand up for yourself—but be polite. And if you're not getting any results, try a different approach or contact a different provider to help. Just don't stand at the hotel's front desk screaming at someone and holding up the line behind you.

More From Smartertravel:

• 10 Basic Packing Tips Every Traveler Should Know
• Nine Travel Products You Don't Really Need
• Seven Signs You're an Annoying American Tourist