If you score 275 or better the Marine Corps will love you. I am a Sergeant that EAS'd in 2000 and I am attempting to become a USMC aviator (snake pilot). I will tell you that I am 5'7" 170-178 and I hate running. Still I run until I dry-heave and that is what motivation is all about. The fastest 3 mile run I have ever completed was 18:30 and that scored me a 297 on the PFT. Do not focus on whether or not someone will be mad at you. If you are in the 275's no one will bitch at you. Anything below though, and you will get your ass ridden a little bit.
Officers are expected to lead the enlisted Marines. OCS emphasizes this explicitly. If you cannot run your Marines in the dirt, you shouldn't be an officer (don't take that literally but more as an ideological viewpoint).
Anyhow, I can do almost 30 deadhang pull-ups. What is the best way to get there? Well other than going to the gym and lifting weights everyday like I do there are a few ways to get there.
1.) Pyramid pull-up routines. Start of with a pyramid like 4-6-8-10-8-6-4 and work your way to something like 8-10-12-16-12-10-8. If you can get to there, you are good to go.
2.) Another method (which still includes doing pyramids if you don't lift weights regularly) is switch-grip. Before I was strong enough to do 20 dead-hangs holding one grip method, I would do about 16-17 palm's down and then switch to palm's up for my last 4-6. This changes the focus from your back (palm's down) to your bi's (palm's up).
3.) Lift weights. Lat pull-downs, weighted pull-ups, bent over rows, etc...
I hope this helps you all.
Semper Fi,
-J