Some analogies between ExtremeProgramming and Traditional Process.

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First analogy: ChristopherColumbus`s expedition.

His ''customer'': The Queen Isabella of Castile
Here, the customer was satisfied having discovered not a shorter route to India, but instead America (the Bahamas).
Here, the customer had to be convinced that the method was feasible (even if risky). 
Had the job description been: Go to India in every case! Then you can guess, that he would have had to go around Africa.

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Second analogy: IndividualTravel versus AllInclusiveTour

Here the customer is the tourist, that wants a satisfying holiday.
He can pick a travel from a catalogue and book a package holiday in some fixed hotel, fixed route, fixed price, fixed everything.
Or he can try what they call individual travel. staying in one location longer if it is fun, exploring interesting locations discovered on the route etc.
You can guess what will normally be more satisfying, even if it has not necessarily a higher risk, but required a (much) higher involvement.

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Third analogy: HouseBuildingAnalogy

You can build a house (among other ways) by letting a StandardHouseBuildingCompany build your house - possibly with some special aspects, say garage, two entrances.
But it will by and large be a standard house, where you will live comfortably, even if not 100% satisfied.

Or you can charge a highly motivated and skilled team of craftsmen (the XP team) with the job and they will build you the house of your dreams modulo the given time and money. If you trust them.

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Add more analogies here, e.g. cereals out of the box - selfmade, ...

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The downside is that even if XP might be the best process for everyone, only less than 10% will do it. 
Simply because people are this way, look at the lot of tourists and standard houses.
People have fear of things they don't know or feel they can't control. 

See WhenXpIsUnpopular, WhenIsXpNotAppropriate