you pretty much have to lead something like double voltage or sincerely higher amperage to pop stuff. that said a lot of modern devices have protection circuits to cut it out if this occurs. If you had as many varied device AC adapters like I do, you'd pop stuff more often. Most likely all of yours are from similar devices. I have chargers for devices that were never released in the US. Obscure shit, and some of them take weirrrrrrd inputs and their powerpacks would break most of my devices (not the 220, talking 110 still)