What does it mean to be a “good” Buddhist? And do you have to come to temple to be a “good” Buddhist?
There is not really any such thing as a “good” Buddhist, or a “bad” Buddhist. We are just who we are. We are just ordinary human beings with a limitless number of limitations. When we realize that I am a limited and ignorant human being then I can go beyond good and bad.
In a relative sense, yes, one should attend temple to be a “good” Buddhist because it is part of the Three Treasures (Buddha, Dharma, Sangha or Teacher, Teaching, Group).
To be part of the Sangha is be part of the Group that together follows the Buddha-Dharma (the Teacher and the Teaching). In theory, one can be an isolated and single Buddhist follower, but it is difficult to feel the support that belonging to a group of “fellow travelers” brings by belonging to a Sangha and attending services.
Additionally, to be a Buddhist means to share the Dharma. We share the Dharma by joining with “fellow travelers.” To have a temple and to listen to the Dharma is a great opportunity and a great responsibility. This is how we share the Dharma with future generations.