Glen says that the doctrine of the Trinity is simple: it's just three persons united in love.
Glen argues that the reason we tie ourselves in knots is because we try to reconcile the 'omnibeing' with the Trinity: an impossible task because the two are not the same.
I'm thankful to Glen and others for giving me a crash course in the doctrine of the Trinity a few years ago and for continuing to teach me. Before, the doctrine was largely a maths problem I couldn't solve, but now I understand it far better than I did. Nevertheless, I still don't think I really understand the Trinity.
In part the problem is metaphysical, but more substantial is the failure of my imagination and experience. Three persons united in love don't exist in the world in which we live. Perfect, self-giving love is something I can barely grasp. I know and have experienced amazing love in relationships, family and church, but the more I know love the more I see how deeply broken it often is. I suspect those of you who are married can list off as many ways in which you are disunited as united, just as I can with my family and friendships. And the church is no exception in its present fractured-yet-united state. So until the sinless new creation I don't think I will ever be able to say that three persons united in love is simple.
In summary, the 'problem' of the Trinity lies not in logic but sin. If you do have a problem with the logic, then its probably not the Trinity you have a problem with.