I want to touch off on a couple of points....
First you would think with the advent of fuel injection that this type of question would be long gone, fuel injection does away with so many issues.
RPM's (not picking on the poster, just a inform) RPM = revolutions per minute so there is no place for the s on RPM's.. BUT I'm the worlds worst at english/literature/grammar so please don't take this as a bash, I just wanted to help with some terminology... I'm ignorant on so many things, so I'm in no way perfect
If I'm not mistaken piston bores are now bored somewhat oval as the produces a better seal than a"round" which can never be true cylinder... Please do some research on this as car manufactures I have read put a lot of research into this. Maybe it's the piston is oval, or the correct term may be elliptical.. this is something worth researching.
Steep hills do not present any more problem than a flat road.. It still takes a certain amount of fuel for the engine to warm up, this is very critical here, fuel=energy, and when the combustion process being so inefficient in a gas engine especially you get heat. If you think a gas engine has a long warm up time try a 3/4 ton or 1 ton truck with a diesel engine, the mass of the engine, extra cooling capacity, and the efficiency of teh diesel make for longer warm up times.
Now when it's cold out, raining, snow etc (snow is rare here) still in the mornings I may let my car warm up in the drive way 10-15 minutes so it will be warm for my kids for school trip.. This is my decision, and if anyone thinks it's a huge waste of gas, etc I could care less because I don't hear many people freezing in their house to save gas..
I'm ashamed of all the bashing of women, and young people on this forum.. As in this thread you have seen a man done the very same thing throttle down, yet it's always a woman that has no idea how to drive/maintain a vehicle !! My mother can extract more mileage out of a car, engine than anyone in my family, all of us are boys.. I have also seen cell phone post as well where it's always a young teenager and then at that most times a female that is texting, or just dumb in general for some reason.. yet insurance rates don't like it's the males that have more accidents.. so that must mean in general women are better drivers ? If anything women are ignorant as to how to maintain a vehicle at the most.. and that ignorance would lead back to those who scuff, make fun of, or in general belittle them because they do not know, as for the ones who do know yet still do it, it's across the board males, females etc.. I'm no NAACP, woman rights, or any other freak, yet just by the postings on this forum I can see why those type of people/thinking exist in the world.. and if you really want to know just how dumb a woman is look at how many males are changing oil for females on this sight, girlfriends, coworkers, etc I commend you, however who has the power in this sector....