Safe first-date topics include number of siblings, where you went to school, your job, and your hobbies. None of them are likely to flag either person as a weirdo right out of the gate. Common wisdom, however, suggests you never, under any circumstances talk about your exes on a first date. But sometimes, the topic comes up. And the truth is, exes are a big part of who and how we date. Relationships, particularly the long, committed ones, are formative in teaching us what we actually want in our future partners.

Although Jennifer Aull, a licensed couples and sex therapist at North Brooklyn Marriage & Family Therapy, typically advises clients to wait until around the fifth date before opening Pandora’s box of past relationships, she acknowledges that if the topic comes up organically on date one, avoiding it entirely can come off sketchy — like you have something to hide. But that doesn’t mean you should say anything and everything, nor should you brush it off if your date does. If the following statements leave someone’s mouth, consider it a warning to proceed with caution.

The statement: “I broke up with my ex because they were crazy.”

The fine print: “Any tone of resentment and bitterness about an ex is really the kiss of death,” says Aull. It may not be a job interview, but what someone says about their breakup — even the body language they use — acts as an informal reference. Calling an ex “crazy” tells tells their date that they lose all respect for a person once their relationship with them has ended. And because the word “crazy” carries some gendered baggage, this is doubly true if the speaker is a cis straight man and the ex is a cis woman.

“If [an ex] does come up, the person should just say, ‘We were together for X years, and it just didn’t work out.’ That’s it,” says Aull. “No unnecessarily weird, salacious details of the breakup and no character assassination.”

The statement: “My ex and I usually had XYZ kind of sex.”

The fine print: It should be pretty obvious not to do this. But factor in nerves, liquid courage, and a general desire to connect with the relative stranger sitting across the table, and oversharing like this does happen, says Aull. “A lot of my clients are these amazing, put-together people, but they’ll still walk away from a date and think, Why on earth did I tell that weird story about something I did with my college boyfriend?” Nonetheless, bringing up sex stuff this early, let alone the specifics of their sex life in a past relationship, definitely indicates an absence of boundaries.

The statement: “Our anniversary would have been last month. We still talk sometimes. It’s totally cool! It’s fine! We’re still good friends. We were just in really different places. We have shared custody of our dog. It was a totally chill breakup. But yeah, totally over it!”

The fine print: “This level of detail comes off like they have unresolved feelings and aren’t ready for a new relationship,” says Aull — and that remains true even if they’re trying to explain that the breakup was amicable. “You want to be open and free, but qualifying statements like these are too sharey for a first date.”

It’s hard to believe someone’s really over their ex if they’re still analyzing the life and death of their last relationship like it’s a 20th century Russian novel… on a first date. “What they should be focusing on is whether they feel any chemistry or interest in you,” says Aull. Save the angst for your next friend brunch and/or therapy.

The statement: “Oh, wow, my ex is really into that movie/book/sport too.”

The fine print: If the example above is a red flag, this is a pink one, says Aull. “Small, thoughtless comments may not seem like a big deal, but they really show where someone’s head is at.” On a first date, both people are looking for signs that the other one has (or hasn’t) truly closed the book on their most recent ex, and this sort of first-date behavior, while not overtly egregious or disrespectful, clearly points to no.

If you’ve been guilty of any of this behavior on first dates, it may be a sign that you’re not ready to move forward yet. “It’s not a hard no to casually bring up your ex in conversation, just be cautious,” says Aull. “You don’t want [your date] to leave thinking about your ex. You want them to leave thinking about you.”