A valley company with an ex-early-google-engineer founder hired me to do ML. It turned out he lied; nothing I worked on for 8 weeks was in any way related to data science but rather pure backend engineering. Said founder actually got super butthurt when I quit 8 weeks in, and had the balls to ask me to stay for a couple weeks to finish projects. After the job description, the interview, and the list of sample projects I'd asked for were all machine learning work. None of which I actually did. This was particularly frustrating because I'd turned down another great offer for them, and it was no longer available after I realized I'd been deceived.