[kgross]

Friction loss in pipe is not hard to think about. The velocity of the water against the side of the pipe is what causes the friction. If you slow the velocity down, the friction goes down. Now increasing the size of the wall, does increase the amount of friction since there is more area, but the decrease in velocity makes up for the increase in area. When it comes to turns, think about your car, a hard turn at high speed throws you against the door, (more flow loss), take that same hard turn at a very slow speed, and you don't get pushed against the door (less flow loss)