For the record, bitterness actually can be a sign of mental ill health, it’s a recognised symptom. Here’s one definition:
Bitterness is an attitude of intense and prolonged anger and hostility. Often, it also involves feelings of resentment and a desire for revenge. Bitterness is the result of a person's failure to forgive another and their allowance of hurt and anger to grow until pain and hard feelings cloud their view of life.
If it helps people to express their bitterness on Gransnet so be it, but it’s more likely to have an impact on threads that aren’t about anybody’s joy at getting new puppies.