I have two: Rollercoaster Tycoon and Zoombinis The Logical Journey For RCT, I loved just the almost endless possibilities with the tracks and and management was easy to understand Zoombinis is just a wonderfully animated game with some great puzzles throughout
Seeing Zoombinis just unlocked a memory deep within me
i had a demo of that game that only consisted of Mudball Wall with different levels of difficulty. Didn't even know back then that there was even more to the game than just that. It was process of elimination.
Mudball wall was my favorite of the puzzles for that game