why best friends are useful

Because you can send them text messages such as this one and they don't (outwardly) judge you...

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Because you have bonded during high school cross country running over the fact that no matter what you weigh, the tops of your thighs still touch...and 14 years later, you still talk about it.

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Because they don't get mad at you when you recommend a gynecologist to them and then recommend their exercise class to said gynecologist.  Hey, when girl parts are your job and you regularly see your GYN while you have clothes on, you forget that seeing people in public who have seen your parts might be awkward for other people.

Because you can regularly check with one another to make sure that none of you are crazy.

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Because they have cute kids so you don't have to.

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Because they also are not afraid to tell you when it's time to send the guy in your life packing (don't worry, not John...someone else had an issue that we took care of).

Because they don't care when you drop off the face of the planet for several weeks because you're too tired to talk to anyone.

Because they willingly have coffee with you every week while your boyfriend is out of the country for five weeks and your two other best friends are out of state indefinitely (which turned out to be temporary...thank goodness). 

Because they don't get offeneded when you start referring to any combination of them as "we." As in, "we think it's time for you to kick jack-ass to the curb."  

Because they don't get all worked up when you don't have enough cash to pay for your $3 drink and they pay for it for you because they know you'll get their $3 drink next time (speaking of which, B I think I still owe you $10 from the time you owed me $40 but only had a 50 dollar bill to pay me with and I didn't have change...or did I?) 

Because without them you wouldn't be able to find a house to live in, you'd get fat from eating poorly and not having any exercise classes to attend, you would know nothing about car insurance, your dog would be without her dog BFF, and you wouldn't have anyone to have coffee or dinner with on weekends you were home alone.  

Added 6/4: Because they let you live in their house with their husband while they are halfway across the country for 6 months.