Goofy or Regular

There are two different types of stances you can have when snowboarding, and it's all determinded on which foot is your dominant foot. If you ride down the mountain with your left foot guiding you, meaning that it is mostly infront, then you are considered to have a regular stance. On the other hand if you ride with your right foot guiding you, once again it means that it's mostly infront, then you are considered to have a goofy stance.
The easiest way to determine your stance is with a pair of socks and a hardwood floor. Wearing just the socks on your feet, run and slide on the hardwood floor; the foot that is infront of you while sliding will be your dominant foot while snowboarding.
Your stance will be consistant throughout snowboarding, surfing, skateboarding, and anything else requiring a dominant foot.