If you started driving pre-1990, before airbags were common, it's likely that the driving instructor's "hands at 10 and 2" command still influences the way you grasp the steering wheel. It remains a popular misconception, but there's a safer way to grip the wheel.
The recommended position of your hands is now at 9 and 3 o'clock, with the thumbs placed along the rim rather than looping around it. In the event of an accident, the force of airbag deployment can send hands at the top of the wheel into your head or even break thumbs.
While we're on the subject, never rest your hand on the hub of the wheel or use an underhand grip while turning—it's a great way to end up with a broken arm in an accident.