Before I got a house, Floppy and family would be taken out one at a time daily on lead. The other cats inside waiting their turn would be at the window screaming to go out. Whenever I took the harness out of storage, they'd all go nuts. After I got the house and built the enclosure, they'd all still go nut foe several years when I showed them the harness and leash.
She's very good...doesn't mind the harness at all and just likes to sit outside watching the world. Bubba is still getting used to the harness and walks sideways when he is wearing it! He was a rescue...found at the side of a road as a kitten, and I think that he is remembering that wild outside of his past.