“Common Knowledge” That Most People Don’t Know

No matter what your job is, it likely requires some form of expertise. Here are some things you should know from the people who do know. Or maybe you don't want to know. Some of the answers are fascinating.

Bridges aren’t attached on both sides: 

They’re traditionally pinned on one side (using 2 super-pins), and rest unfixed at the other end. This helps avoid additional stress as the bridge flexes, or expands/contracts with temperature change.

Airplanes are fixed with duct tape: 

They develop cracks. It happens. If in a non-critical area, standard procedure is to put some fancy duct tape over it until a repair can be done.

People get hacked, not the device: 

Most hacking is done by tricking the user, not the computer. This includes credit card hacks.
No website or app really stores your password. That’s why they can’t show or email your password to you. They do a 1-way scrambling of your password, and store that.

Don’t get married near Valentine’s Day: 

The flowers will be twice the cost, and half the quality. When buying roses, if the head feels squishy, it’s no good.

Your home lock is easy to pick: 

Most people could be taught to pick it in 15 minutes.

Don’t rinse after brushing: 

Don’t use mouthwash, either. Just spit, and leave the rest of the fluoride on your teeth for more protection.

Collision coverage isn’t always worth it:

 If your car is 10+ years old, collision is generally a lose-lose proposition. It can double your cost, and in an accident, your car will probably be totalled anyway. 

Why plane tickets go up in price while you browse:

Airlines don’t raise their prices because they see you looking at a ticket in order to panic you into buying. They use a system from the 70’s that requires you to take a seat out of inventory in order to see the price, and if you don’t buy, the seat doesn’t go back right away.

So if you check the same flight on 10 different sites looking for the lowest fare, there could be 10 seats that have been taken out of their inventory, which triggers an automatic price increase.

About half the time, if you just wait until the next day, the seats will go back into inventory and the price will go back down to what it originally was.