When the other half borrows the car, she adjusts the seat back height, and horizontal slider. I can always find the right position from this because I have the seat all the way down and can easily judge the horizontal slide with the position of my legs.
When we first shared a car though, it was terrible - she would move the steering wheel, recline, everything and I would be so uncomfortable for hours, even to the point where I'd get aches (Although, I'm sure most were psychological).
When I took my car to Ford a few weeks ago, the Manager took it out so I could demonstrate a noise it was making - he adjusted everything, to which I complained that he was supposed to be taking the car out as part of a diagnostic, not to get comfortable and have a nice drive - he was completely perplexed as to why I was so angry about him adjusting my seat. When the VXR went in to VX, the head tech (the only one who would work on my car) never moved it in the slightest - I'm sure it wasn't that comfortable as he was a good 5-6" taller than I, but I had the utmost respect for someone who respected my vehicle in such a fashion.