Last Thanksgiving, Americans sat with their families, gave thanks for the bounty and talked about bitcoin. At least it seemed as though people everywhere, young and old, were suddenly interested in cryptocurrencies and wondering if they should board the decentralized currency train. There were even guides about how to discuss cryptocurrencies with your relatives at dinner.

It made sense.

Bitcoin, the marquee cryptocurrency, was trading at an intraday high of $8,267 last Thanksgiving, up a mind-boggling 724 percent since the beginning of 2017, according to CoinMarketCap data. After a post-Thanksgiving rally it hit $10,000. By mid-December that amount doubled to nearly $20,000.

It seemed like it was going forever up and to the right. Until it wasn’t. Bitcoin — along with other cryptocurrencies like Ethereum and litecoin — spent most of 2018 in a slump.

Two days before Thanksgiving this year, bitcoin is trading at $4,577, or 77 percent below its peak.

So in case the people around your table bought into crypto last year and didn’t get out in time, it might be a good idea to treat the subject like politics, keep quiet and pass the gravy.