Myself liked to do 0-fee txs, just for fun.
I remember the days when an input had to have "medium priority" to be able to add other inputs up to 1 kB in a zero-fee transaction. It's too bad the concept of "coin days destroyed" was bandoned in favour of higher fees. It was a good feature, as it rewarded using older funds, while discouraging rapid (spam) transactions.
I gave up on it before it was abandoned, after some of my transactions got stuck for 2 weeks and I had to double spend them to get them confirmed.
I entered Bitcoin just at the tail end of that... still remember priority values on blockchain.info. I too thought the idea of older coins having some weight in priority was a good thing, but was never able to enjoy it myself. All coins acquired were ever fairly new. Suppose scaling upgrades mean spammers have to get ever more creative now.
I believe the antpool "acceleration" submitter still works even for 0-fee tx now, so in the unlikely event someone inadvertently managed to make such a tx, there's still that one avenue for confirmation.