After accidentally invoking Siri on my iPad mini for the fifth time this morning, it hit me: The proprietary layout of buttons on the Samsung Galaxy Note II that I just reviewed is making me stupider at using Apple’s mobile devices.

Samsung veers from the lineup of Android system buttons that Google established with last year’s Ice Cream Sandwich release: Instead of back, home and recent apps, arranged left to right, Samsung’s Android phones offer menu, home and back buttons. (LG also departs from the Android standard, but its back-home-menu array keeps the back button in the expected place.) To see your open apps, you have to press and hold the home button.

On my iPad mini, that same gesture opens Siri, while I have to tap the home button twice to see open apps.

(Yes, when I first wrote about ICS, I was skeptical about removing the menu button and thought that requiring a long press of home to see open apps was good enough. I was wrong: I rarely miss the menu button, while I hit the recent-apps button all the time.)

It’s an exasperating situation, and if I were to get a Samsung Android phone and keep my iPad I’d have to waste brain cells on memorizing this unnecessary difference. You can’t remap the system buttons on a Samsung phone or change Apple’s home-button behavior;  if you disable Siri a long press of the home button will instead bump you over to iOS’s search.

If, on the other hand, I get a phone with the regular ICS buttons–many vendors alter Google’s interface in other ways but stick with that lineup–I face a lot less confusion. At worst, I’d find myself pressing the phone’s home button twice and having nothing happen, which beats launching an unwanted app and hearing Siri’s “ding-ding” prompt.

So that’s one thing that I know will govern my next phone purchase.