Devices that don't follow USB-C standards
We've all been there. You buy a "USB-C powered" device. You look in the box and there's a USB-A to USB-C cable. You toss the cable in to a drawer and plug your new toy into the setup that works with everything else you own. It doesn't charge.
Many manufacturers cut corners by omitting essential components like the CC pull-down resistor (required by USB Type-C Cable and Connector Specification). They don't even need to implement USB-C Power Delivery - they could draw 15W if they used the right resistor values!
You were promised the ability to travel with just one cable. Let's name and shame the offending parties.
BadBrand
Claims 65W USB-C PD but only outputs 5V fixed voltage. No PD negotiation chip installed.
CheapTech
USB-C port is power input only, no actual USB-C data or PD pass-through support.