Right side hand controls should have a brake hold feature. Because how else can you shift in/out of park and reverse? With left side hand controls you can hold the brake with your left hand and shift gears with your right hand. Last but not least, left side hand controls enable to you to control the gas, brake, and steer all with the left hand (not recommended for long but doable for a second) so you can shift a clutchless manual transmission, adjust the radio, climate control, or just sip your drink with your right hand.