But why would you choose the red one, over the white one?
Why is it impossible to choose the white one, just because there is a red one?

Is it because you've never had a red one?

lol

It is impossible to travel in time and make a change, because of the implications of the time-space continuem; you are but one tiny piece of the whole, and therefore you alone could nopt change an outcome from a past decision - everyone would ahve to go back in time, and make all the same decisions just to ensure that your change can be implemented.lol
What if the ice cream vendor decidied not to serve you, if he went back in time? Then you could not make a change in your decision, thus the time-space continuem is upset, and the ramifications of such could render you in a void of non-existence.
You would arrive at a point in time, where you have to make a choice that isn't there!
You'd be stuck in limbo

lol