What's a successful brainstorming session you conducted, and why do you consider it successful?

As a Fresher I didn't conduct any brainstorming sessions but

 In my opinion, A successful brainstorming session is when everyone puts their point and efforts into the discussion without any hesitation

In brainstorming sessions, colleagues or juniors openly criticised the point raised by me in a friendly manner without any hesitation and the talk is aligned to the point or participants always stick to the topic of the discussion. Any personal agenda not satisfying the discussion.

A successful brainstorming session must have these things

1. No personal agenda must be satisfied.

2. Junior or colleagues raise their point without any hesitation.

3. Discussion must be around the topic.

4. Active participation of every member is required.