I have a K1000 and before that a Pentax S1a (1968) that makes a K1000 seem like a P + S.:-)
I now have a K10D and there are so many settings on this camera to 'customize' how, what you want to make the camera do that you can set it to your hearts content. I've had my K10D over a year and I'm still learning...I love it.
When I first got it, it was quite a challenge for me, even though I've been a serious hobbyist for 40 + years and have many mechanical cameras...such as Mamiya-Sekor, Leica, etc.
I'm older and I found the K10D's electronic menus, etc. confusing. The manual was ok but still written a little over my non-electronic head.
What worked for me to explore what the K10D could do, was to get a K10D book by Yvonne Bourque and also get the Peter Burian book on the K10D from Magic Lantern.
I've gone through these books, along with the manual, page by page...reading and then trying things out. It's worked for me and I enjoy the K10D much more, knowing how to use it to it's utmost.