We judge others by their actions, ourselves by our intentions.
Coincidentally, I am 35 and feel the same way :) Most of us are just working hard to get through the day and we're all going to screw up sometimes. I always try to offer understanding for others' mistakes, and hopefully I'll receive the same.
Don't give an objective analysis of the situation with an account of the other person's point of view, especially if your wife or girlfriend is in the midst of emotionally venting. It won't be appreciated.
Once she's cooled off and feels listened to and heard, then you can start to reintroduce logical analysis and 'what was the other party thinking and why did they do what they did'. But not right away.