Red flags in job interviews

Weird one but... What do red flags during an interview look like you as an applicant?

I had an interview today .. Well informal chat and the person selling the job.. His opening line was " you'll be making tea and coffee for staff and guests/ visitors..." - I'm a female roughly same age as this guy interviewing me and it was a family run business, there wasn't much else to the informal chat and it felt like he dropped a few borderline sexist comments along the way in terms of childcare and asking me what time my son gets to school for..and I'll also be the only female in a male office but it lts got me thinking.. What does a red flag interview look like? The guy was genuinely nice but my gut's telling me it's a potential red flag.

I'm compiling a list for my own personal job search journey as I have trouble judging what's a red flag and what isn't etc so it's almost like I've got a guide to job interview red flags effectively.