h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Someone has already done it.

Mayonnaise is the give away. (I have known this for ages).

Look, no-one in their right mind ever said: "I wonder what happens if you take the yolk of an egg, beat it with the merest smither of vinegar, and add olive oil ONE DROP AT A TIME? I have the strange idea that it just might make a greasy gooey alternative to oil and vinegar for dressing salads"

Puh-lease!

The only rational explanation for mayonnaise is time travel.

I... I...

I will just HAVE to shut you up young lady.
How the hell did you find out about my plans!

yes of course, that too.

Yes and Bill Gates is proof there are aliens

I do not think that mayonnaise is the worst offender in this particular line of thought. I mean really, egg, and oil and vinegar are all things that people readily and willingly eat all the time. But some things you'd just have to be plain daffy to think about trying in the first place. Take for example Vegemite. Now I know that yeast has been around for a very long time and it does all kinds of really yummy things (i.e. bread, beer, penicillin) but who thought it would be a good idea to just skip the middleman and go right for the yeast itself. Now I am sure that some of you out there just love the stuff to death, but I myself can't fathom the reasoning behind it all.

One of the things that always made me wonder "what were they thinking?" was whoever thought of eating eggs in the first place? "Hey, look what just came out of this chicken! What should we do with it? Fry up the innards?"

Of course, this raises another interesting question. If someone brought Mayonnaise (or Vegemite) from the future, then obviously, noone has invented it, it was simply there. But if noone invented it, then how the hell did someone send it back through time in the first place? God I hate temporal mechanics...

Aliens from a planet where mayonaise flows like water will bring it to Earth, who (having discovered how to reproduce it) will send it back in time to benefit humanity?

That, my dear friends, is what I have been waiting for. You really found it out. Where I come from, there are indeed rivers of mayonaise. When I got here 142 years ago I saw you guys had rivers full of water. What a shame. So I invented a way to make up for it. It's not quite the same thing, but close enough.
The point is, mayonaise, like myself, is not the proof of time-travel, it's merely the proof of the existance of other planets and life in other parts of the universe.
I just don't get how you earthlings could ever think that you're alone here. There are though open-minded people on this planet. It's nice to know that...