Pick Angling
I only ever angle the pick when doing tremolo because it makes the pick roll smoother across the string and reduces the attack volume slightly. If I want to use less angle, I turn the pick around to a round corner.
If the guitar is slung at the proper ergonomic angle for playing, like classical (which few do because it doesn't look cool), the pick wouldn't be at an angle. If the pick is at an angle naturally for you and you are fighting it, the guitar might be slung too low. Not that I'm telling anyone to change, just pointing out one reason why it is happening.