I usually buy my groceries without a shopping list. I walk around the aisles, taking both what I know I need and what I don't know I need, that is, ingredients and products which I want to try. This worked well for me when I shopped for myself, because I have no problem (and even enjoy) improvising meals on the spot.
This changed when I came to live with my grandmother. If I forget to buy sugar it's a small crisis and no, sweetening her coffee with honey is not an option. "Write things down dammit! You can't remember everything!" she would growl. I hate lists and feel much more comfortable improvising, so it took me a long time to adjust.
Now that I've done it for a couple of months I understand there's virtue in not having to hold everything in your memory. In every shopping list there's crucial items and nice-to-have items. The crucial items cause a certain degree of anxiety, "I must not forget to pick up some milk" you may find yourself thinking throughout the day.
But today I got to the grocery store with a bit of time to spare. I did as I did my shopping before: I wandered the aisles and relaxedly picked up what I knew what was on the list, but also what I didn't know needed to be on the list. "Oh, paper towels, I'm sure I'm on the last roll, better buy some". Then, realizing the grocery store will be closed on St. Jean Baptiste Day I made some advance purchases, otherwise tomorrow I'd be carrying too much stuff back home, or even run out of supplies because on the weekend we are celebrating my grandfather's funeral, and I'll surely be short on time.
When I was done getting what I thought I needed I took out the list, and was satisfied to see I had picked up everything written down on the list, plus many other things that were outside of my awareness. I notice one way is not better than the other, and that they are not mutually exclusive, you can both write things down and act out of intuition.
This applies not only to shopping lists, of course, but to a certain way of being which I shall call execution mode and discovery mode. You could go on vacations and have a list of places you want to visit, but you must also allow for spontaneity and not sacrifice relaxation in the name of completing your bucket list.
Lately I've been thinking about these polarities. My grandmother is my polar opposite in personality and habits, and out of the need of peace I've accommodated to her style. There's a calendar hung up on the fridge with all her appointments and daily measures of weight and bowel movements. My calendar is on my computer, and I only use it to register my friend's birthdays. By learning her style I have not abandoned mine, it has been enriched by another way of being.
All polarities are meant to be transcended and included. This does not mean walk the middle way, it means walk above the way. Beyond left and right, beyond good and evil, beyond joy and sorrow, beyond logic and intuition there's another path with integrates both.