The entire point of "muscle memory" is that you don't think about it at all - I think "close window", and the cursor moves to the top-right corner of the screen and clicks the box without any further attention from me. For more sophisticated stuff muscle memory becomes more more of an analogy, but it remains "click on this icon that does X at aproximately Y location" and needs minimal thought - just rearrange things and you have to spend time playing "where's Waldo" with the icon you need. Change the icon graphic as well, as is so often the case between analogue tasks on different OSes and it becomes an even more attention-consuming endeavour. Change the basic process as well, which is not entirely unheard of and you may need to relearn large portions of your skilset (for example Open Office, WordPerfect, and MS Word all use fundamentally different underlying concepts of document organization, which is very often reflected in the UI workflow)
As for laziness - the entire history of civilization is one of laziness, even multiplication was a shorthand technique developed to simplify tediously repetitive addition. Adding superfluous difficulties, even superficial ones, is both annoying and dramatically reduces productivity. Yes, it may often come down to remembering new locations for similar-looking icons, but even that is a non-trivial expenditure of attention, especially if you're not good at memorizing new things.