IOS4.0.x: I just don't understand. Please explain...

Question

...how exactly the same hardware (give or take physical tolerences) loaded with exactly the same software, can run differently on everyone's phones?
So many people are saying that they've lost this, lost that, this doesn't work, that doesn't work.
Surely all phones should be exactly the same shouldn't they? It's exactly the same software going onto everyone's phone so, assuming there is no third party software interfering with the Apple processes, they should all behave the same way.
Why do they not appear to be doing that?
Just asking

Answer 1

Surely all phones should be exactly the same shouldn't they?
Assuming no defect, the hardware would be the same, yes, other than the size of the flash RAM. But some devices do indeed have hardware defects, some obvious and some very subtle; for instance, a small defect in RAM can cause all sorts of strange problems not easily traced to a specific hardware problem.
It's exactly the same software going onto everyone's phone so, assuming there is no third party software interfering with the Apple processes
That, however, is an assumption that it is incorrect to make. Very few people have exactly the same load of software, since few people have no third-party apps at all. And misbehaved apps, or corrupted cache or data files (which could occur even with nothing but Apple's software on the iPhone), can cause problems, something which has been well established by the number of people for whom restoring their iPhone as a new phone rather than restoring a backup has cured the problems being experienced.