So many gadgets...
Like the early iPhone that had a recessed headphone jack, preventing you from using any headphones other than the ones that shipped with the phone.
Or any number of "music phones," feature phones with MP3 capabilities that often don't even have a 3.5mm jack. Many have a 2.5mm that requires an adapter. And while we're at it, a lot of those phones had locked-down software that made it difficult to even get music onto them, and that didn't even matter since many shipped with tiny memory cards that also couldn't be accessed unless you pull the battery. There are still many smartphones that require you to pull the battery to get at the memory card.
Also requiring an adapter for headphones was the GameBoy Advance SP, which combined the headphone port and charging port into a single clusterfuck port, ensuring you couldn't use headphones and charge it at the same time. Unless you bought a third-party accessory that split the headphone and charging functions (first-party Nintendo accessories only let you do one or the other, not both).
Speaking of Game Boys, how about the original GameBoy Advance, whose screen was basically impossible to see unless you had absolutely perfect light hitting it.