This has me thinking in areas where I don't usually go, and that's a good thing!
Almost everything I put into a reading beyond pure flashes of intuition arising from the card images and their combination is "memory-based," coming from my experience (both life and tarot), my tarot knowledge base and my philosophical, historical and cultural storehouse of ideas that I draw on for metaphorical expressions. It's how I bring inspiration, imagination and ingenuity together to tell a story from the cards.
I think a lot of people do. I've read a few different tarot books that suggest associating card meanings with people you know or experiences that remind you of the card.
I'm interpreting projection here as using personal experience to help inform your interpretation, rather than going on gut intuition. I can understand why generally this is something to be avoided, but its actually a very integral part of how I've been taught to read and I feel you can use your experiences to interpret without replacing the sitter's situation with your own.
For example, when the Queen of Wands shows up in a reading, I immediately think of my aunt Susan, and how she was the kind of person who would let me and my sister have ice cream for breakfast or pick out a toy we wanted at Target. She was very laid back and very accommodating. That energy can be relevant to my sitter's question. It may come up in his environment position. So I could interpret that environment around my sitter as similar to Aunt Susan in that the authority figures in his life allow him to have a lot of freedom and indulge him in some ways.
The way I keep my emotions from coloring the reading is by remembering that even though I like Aunt Susan's energy, my sitter might not. They may need someone who can give them discipline and enforce boundaries. As long as I'm aware of that, I feel I'm still being in service to the sitter, as opposed to just reading myself, which I think is most people's fear when projecting.