How do I allow for spontaneity?

I’m really seeing the value of planning and making decisions with my prefrontal cortex and then sticking too them. I want to develop a relationship of trust with myself and can see that this is going to really help me but I have a tendency to become too make things too serious and can see myself over planning and not allowing for spontaneity. I can also see myself using spontaneity as a fancy excuse for buffering. Any suggestions on how to keep spontaneity in my life, keep my relationship with my primal brain fun and still stay the leader?