Amazing question, the truth is I've always had issues with forgetting things a whole lot, and anytime I travel I find out that I left in so much hurry I forgot the things I should be taking for my journey which makes it very difficult to go about my business.
I've learnt that while travelling one must be very cautious and very calm not being nervous before the journey so as not forget important things like maybe travel documents, money to spend on our journey or forgets things that may make out travelling seems fruitless and futile