“Why do you want this job/to work here?” “I’m just looking for something interesting to do for a while, get out of the house a bit. This sounds interesting enough.”

They hear: I don’t need a job, I may not need money, I may already have a job, I’m not picky about where I work so I’m probably not planning to stay, I’m likely to be weird or high maintenance, I’m very likely to move on quickly if I’m no longer entertained, and most importantly, I don’t need this specific job so I won’t take abuse of any sort.

This does work to land food service jobs, though, because they don’t really care. They gain and lose staff so frequently that if you just aren’t a complete shitshow you’ll get the job.