I ignored advice to buy BTC when it was about $200. I ignored it again when it was about $400.
To say I'm a bit wiser now about such things would be the understatement of the year.
Oh and I did have a coin wallet app on my phone and lost the book where I'd written the keys down. What did I do next? Lost the phone of course. That was a $300 mistake.
Life in crypto eh? What a giggle ;)