ATTI mode mentioned earlier, if you're not sure what that is or haven't flown in Atti mode I would MOST certainly research it. It's basically flying the drone without it breaking, meaning if you send it one direction the only way to counter that direction is to move the stick in the opposite direction. No breaking when you release the sticks. Super easy to lose control and have no idea why you've lost control.
The first time I went up without satellites and my
M3 went to Atti mode I literally had no idea what the hell was going on. Luckily I was way out in the desert and no structures around. After about 90 seconds, I was able to determine what the heck was happening and able to counter its movements and finally land. In an urban environment I would have crashed it into something...no doubt.