what is the difference between left bank and right bank of a river

Basically, when you are on the water, upstream is always the direction against the current, like heading towards the source of a river or a stream. It is like trying to push yourself against the flow, which takes a lot more effort and fuel because the water is constantly fighting back against the hull. Whenever I am navigating, I always have to keep an eye on how the current is pushing us, because heading upstream definitely changes your speed over ground quite a bit.

On the flip side, downstream is just going with the flow, moving towards the mouth of the river or the sea. It is much smoother sailing since the current is actually helping you move along. You will notice that your speed increases significantly without having to push the engines too hard. It is pretty much the easiest way to travel, but you still have to be careful with steering because the water's momentum can make things a bit tricky in tight spots.