When would one use 2nd or 1st gear when driving an automatic? In all the years I’ve been driving automatics I’ve never used anything other than park, reverse, neutral and drive.
Pulling a load, 'specially through a mountainous/hilly area.
Also, it’s a good way to slow down your vehicle if your brakes crap out.
It’s also good for slowing down when you see a cop and you don’t want your car to nosedive and your brake lights to light up the night sky saying “HERE I AM COME GET ME!!!” (Of course this only works if your going, say, 10 or 15 over, anymore then that and you probably won’t be able to do it fast enough with out killing the engine)
Up or down steep inclines. Going up, more torque, going down, engine braking.
Getting traction in snow.
All are good, the traction in snow is more for the auto’s that are in 2nd when the selector is in 2nd, as opposed to first or second.
Also is useful when you know you will need a shitload of accereration, like when you are behind some a-hole going 45 in a 55 with limited passing lanes. If you see one ahead you can shift into 2nd to get a quicker jump when you floor it to pass.
“When would one use 2nd or 1st gear when driving an automatic?”
Otto, have your read your car manual?
When going up or down an incline, you need lower gears, just like on a manual shift car. Basically its easier for the car. Sure, you can’t get away with not doing it. Also shift before you hit the slope, not in the middle of it, as some of my friends do 
I grew up in West Virginia, which has about 4 square feet of flat space in the entire state and everything else is on a steep hill. Sometimes an automatic won’t pick a good gear when you are going up a steep hill, although most of the time it will and you don’t need to override it. Going down a long steep hill can make your brakes overheat, so a little help slowing the car down with the transmission can save you some brake pads and warped rotors. Using the transmission to slow the car in general though isn’t really recommended. Instead of replacing brakes you’ll end up fixing your transmission. Only do it when necessary.
Where I drive now (PA and MD) it’s rarely necessary to use the lower gears.
I live in flatter-than-a-billiard-table Florida, but I tend to use it a lot for overtaking on a single lane road…
You drop it from drive to third, floor it, and it holds third gear longer (some automatics will automatically drop back in to high-ratio when you hit the rev limiter) and poof you’ve passed that truck.
I was told once that it is very hard on an automatic transmission to haul a load uphill. If you manually shift to 1st or 2nd, that takes the load off the bands and stuff. Does anyone know if this is true?
It doesn’t take load off; it simply keeps the engine from jumping into 3rd/4th (or possibly fifth)…
If you get into third gear with a heavy load, you won’t be able to increase revs fast enough to get the engine to kick back down, and you might get stuck at 30 mph pulling onto a highway or something… thus you manually restrict the engine to low ratio/high revs.