Typically it's the kind of sales work hackers dislike. But plenty of people have built good careers around a sunny tolerance for rejection. Real estate agents, insurance sales people, cold callers, door-to-door sales people -- all of them experience many rejections for each closed sale.
One successful sales person told me that "it's just a numbers game." I still think about this with every rejection I receive.
It's vanishingly rare that rejections are actually personal in any real sense anyhow. At least when business is concerned. Heck, even when they know you, it's rarely personal - personal circumstances and biases are a far greater factor than any real animosity.
Except for a few comical asides, you never remember the no's anyhow.
This leads me to an idea: What about if a bunch of hacker entrepreneurs got together and agreed to try to sell eachother's products? It could actually be fun to try to pitch something where you have no emotional investment in the product. Naturally you would do your best to succeed and agree to document all the responses from prospective clients.
Congrats, you've just invented the salesman :-) Joke aside, it might be fun to try to do some sales time to time.
If the object of the game is to learn how to feel comfortable being rejected by people then perhaps it's better to not include rejections that result from policy in your score.
For example, if you ask for a discount in a store and the clerk rejects you, they are just acting on store policy, not giving a personal reaction.
If you sell door to door the person who tells you to get lost is most likely rejecting what you are selling or rejecting the idea of being harassed by a salesman, rather than rejecting you personally.
Or "marriage."
I don't get why the joke would be funny, I would find it sad if true and bizarre if made up.
I'm not a "sale type" but I've actually been doing some part-time canvasing lately just to have the 'getting over the rejection hump' experience.
It's easier and more pleasant for me since sales still isn't my job.