the appendix provides an excellent location for some gut bacteria to survive when we experience diarrhoea or similar complaints. This way the gut may rapidly be recolonised. Also i don't think evolution necessarily removes useless features which aren't detrimental to survival, I don't believe we have any use for wisdom teeth any more for example
You know that business whereby whenever you are sick it always includes carrot. even if you can't remember the last time you ate carrots?
Well, every time you eat a carrot, it is stored in the appendix until it's required for vomit-enhancing purposes, at which point, it leaves the appendix and re-enters the gut.
I just had an emergency cholecystectomy (gall bladder removal). I asked the surgeon, "If we can live without it, why do we have a gall bladder in the first place?"
He replied, "For the same reason we have an appendix and a spleen."
This illustrates the old fallacy that evolution has a purpose or an intended end result. It doesn't. It comes about by the process of random mutations from the norm, followed by natural selection. If a mutation is beneficial to the organism it will burgeon and posibly take over the organism altogether. If not then it will either be detrimental or have no effect.
If a human being is born without an appendix and that human being is able to survive better than his fellows then his 'better' form would be reproduced ad lib in his descendants. But as it happens it doesn't matter two pins whether a human has an appendix or not, so evolution has no part to play.
tonsils are the first port of call for throat infections, remove them you can get pharyngitis.
Alternatively, when purchasing a piece of flat-pack furniture,, there are always at least two screws left over.