What are some signs that a therapist may have poor boundaries with their clients?

Serious disappointment when the client cancels a session.

Struggling with fantasies of deeper connections with clients, whether sexual or parental or other intense or intimate relationships beyond psychotherapy.

Failing to mention the client in supervision/consultation, out of fear the supervisor/consultant will advise return to ordinary healthy boundaries.

'Happy Days' star Henry Winkler took Marlee Matlin in after difficult relationship with William Hurt - AOL.com

Obsessing about clients outside of work hours.

These items can happen fleetingly, briefly, in any therapy, but if they’re frequent, it’s definitely time for the therapist to get some good, solid supervision/consultation.

Eager anticipation (or anxious anticipation) of the next session in ways that distract.

Were the 1980s as uptight and prudish as movies and TV shows make them out to be? When I think of 80s culture, I think about a very "icky" judgmental yuppie status quo time period.

Session-expressed curiosities about client details not relevant to the therapy.

Off the top of my ancient head:

General Introduction to Boundaries from Panahi Counseling:

Why do flat earthers delete their answers after being proven wrong? Are they just being ignorant and arrogant?

Sense of competition with persons who are important in the client’s life.

Frequent phoning or texting of clients to “check up on them and make sure they’re OK.”

Disclosing feelings, fantasies, and experiences to the client in ways not related to the work the client is engaged in.

What should I do to stop being angered easily?

Routinely going over the time limit with certain patients, compromising the time for the next client.