I have already asked the question “X won't Y” (able/willing) vs. “X doesn't Y”, and now I want to extend the question to further meanings/usages of will (according to the Cambridge Advanced Learner's Dictionary).
So, the question is if the following example sentences can be rephrased by plain verb forms instead of will. And if yes, is there any meaning difference between the original and rephrased version of the sentence?
Accidents will happen.
Fruit will keep longer in the fridge.
Fruit keeps longer in the fridge.
Will you stop being such a pain?
You'll go upstairs and you'll go straight to bed like your father told you!
Stop being such a pain!
Go upstairs and go straight to bed like your father told you!
This quantity of lasagne will feed six people.
This quantity of lasagne feeds six people.