This may sound pedantic, but bear with me (I wish someone had given me the nickel speech before I left for basic...).

Keep in mind while you're doing all that "shit" work in basic and all the running and other crap that just seems like it's a means for the drill sergeants to be mean and degrading that there are basically two forces at work:
  • They're trying to equip you with skills that will keep you alive later on, not all of which they can explain to you every 15 minutes when the answers aren't obvious; you'll get answers later; for now, learn the routines. It is an exceptionally rare case that your instructors are just mean old bastards. Remember the gunny's words to the guys at the end of the training phase in Full Metal Jacket? He's congratulating them for becoming something worthwhile. That really is their goal. Give them the respect to assume you're not the first person who ever thought a DS wasn't being fair or nice.
  • It's up to you and your squad/platoon mates to keep each other squared away. If you see someone fucking up, help them out as a team instead of letting them fuck up. Because if you let them fuck up and the Drill Sergeants find out about it, you will ALL pay the price (as you worthless scumbags should).

Aside from that, basic is more or less a mental game. Can you learn the very rudimentary skills that you will need later in advanced schools while being kept in a sleep-deprived and physically exhausted state? If not, you really have no business being in the military. And yes, that goes for personnel pukes, too. They also serve who file and type.

Oh. Also keep in mind that there are only two ways to get out of the army and not have your separation be a black stain on your record:
  • Medical (wounded, injured, physically incapable of performing duties)
  • End of your normal contracted 2-8 years of service.

EVERYTHING else, including whining to mommy and having your senator/rep call the base and get you out all result in "general" or dishonorable discharges, which employers frown upon. So suck it up and deal, even when things look bad.

One final note: don't forget to think/duck. I moved into a headquarters company after driving tanks for a bit and had my sergeant major give me a pen and tell me to write something on a lexan calendar in precisely 1/4" print, all caps. I was so focused on the 1/4" all caps print that I didn't look to see the pen was permanent, a fact that caused me no end of embarrassment when he said, "Now erase it all."

And good luck. You'll meet some mighty fine folks in the service.