It depends on what is involved. If it is a relationship, I prefer to go with the flow because no amount of planning can determine the success of a relationship. I let it go and enjoy the moment while if lasts and believe that if it works out, all good. On the other hand if it has anything to do with a job, a journey, an interview even something as trivial as a shopping I like everything to be carefully planned. I want to make sure I have crossed the T's and crossed the I's and checked and double checked my list to make sure I'm very prepared. I don't like to be taken by surprise.
If it's my journey, I arrange my stuff a night before, check my accommodation bookings and my transportation details before embarking on my trip. I'm a thorough person and I'm very thorough when it comes to certain things.