When driving a car in the US, we drive on the right hand side of the road. When operating a boat, the normal traffic on waterways is counterclockwise which is basically the same as driving on the right hand side.
Watercraft leaving the shoreline must yield the right of way to any craft not under power, unless the unpowered craft is overtaking the powered craft which once again is similar to the rules of the road in that if you are driving a car you are not going to pull out in front of other cars that are traveling fast on major streets. Instead you will wait until the coast is clear and proceed, the same rule applies on the water.
One major difference between the road and water is that watercraft may pass on either side when overtaking another, but the operator of the passing watercraft is responsible for any collision resulting and for his wake. Watercraft being overtaken must maintain course and speed.
This is different from the road in that we are taught to only pass on the right however on the water one may pass on either as long as it is safe to do so. Finally, watercraft meeting head - on must pass portside to portside when practical to do so.
Overall, the rules of the road and water are fairly similar, but if you do not recognize the similarities because you see a boats appearing to drive every which way and it looks like chaos, you can easily put yourself and others in the boat with you in harms way.