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

Serious disappointment when the client cancels a session.

General Introduction to Boundaries from Panahi Counseling:

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

What are some alternative ways to express gratitude or acknowledge thanks in English or French without using the phrases "thank you" or "you're welcome"?

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.

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

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

What is the STAR interview method?

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

Obsessing about clients outside of work hours.

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

Do any members of BTS have significant others in real life? If so, why do they choose not to discuss it publicly?

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

Off the top of my ancient head:

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

The Roman Empire at the time of Christ kept meticulous records. Why then, is there no record of the trial of Jesus?

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