Attending supervisor's group meeting after thesis approval
The general rule: go if you think it would be useful to you, though it would probably be polite to check with the supervisor first:


  "Is it ok if I still come to lab meetings during my thesis-pending period [or whatever it is called in your location]? I'd be interested in keeping up with the work the group is doing."


Usually I would expect the supervisor would be glad to accommodate you. And even if you are not reporting on any work of your own, you might have useful input regarding other people's work.

In your particular situation - "he got really mad at me" - for whatever reason it does not sound as if you have a very healthy relationship with your supervisor. So it's probably in your best interests just to move on. It's hard to say how your supervisor might feel about that, but in this instance you are better off thinking of yourself rather than trying to maintain an unhealthy relationship.