Fishing a river makes you realize where fish usually reside, which is fairly predicable. Lake fishing however is much harder IMHO, the fish have an additional 3D effect (suspending) that river fish don't have. River fish are only about 2 1/2D at best. There aren't many rivers I fish over 10-12 ft deep.
Have never had my butt kicked so bad on a river, but in a lake it happens often.