Agree with previous post.
Many of the small HDMI displays don't properly implement the feature where the device returns a valid EDID block, which is how the display explains what resolutions etc are supported or preferred.
Mostly, once that is sorted, the touchscreen is either SPI (so the Pi physically attaches via the GPIO port, or USB, where it is plugged in and the magic USB stuff just detects it and loads the relevant drivers. [Obviously, that last part is a gross oversimplification].
No, I can't think of anything funny that won't offend someone if they want it to...