Ditto, although in my case it's the Mirrycle handlebar mirror. I have one that I've swapped between two bikes. Feels nekkid when I ride the bike without the mirror. And an old neck injury makes it difficult to peer over my shoulder.
To make it easier I'm going to try a helmet mounted mirror, which I've avoided for years. I like the Mirrycle on the flat bar hybrid, which has relatively narrow bars. But it feels too wide on the other bike with wider riser bars when on the local MUP and in group rides. I recently hooked a fellow cyclist in a group ride when we converged on a narrow MUP path from different ramps. No harm done, but the slight clash with the handlebar mirror made me reconsider trying a helmet mounted mirror instead.
I also usually attach a Lowepro padded lens pouch across the handlebar via a wide Velcro strap. Handy for my phone, external USB battery, compact camera or other doodads I want handy, but don't want to carry in a pocket. Occasionally I've had both pouches on one bike and none on the other, which feels odd. I used to carry those pouches on a belt while walking so after many years of use I'm accustomed to them always being with me.