RetroArch the emulator "wrapper" has an option to enable an NTSC filter over the image, simulating the visual look of a composite NTSC signal/TV. Here is a comparison between the "raw" (no filter) mode and with the filter turned on:
Note how it's not some simple "blurring" or "anti-aliasing" filter.
Although I'm not exactly sure how different NTSC and PAL look, I'm bothered by the fact that it says "NTSC" and not "PAL". I'm sure that there are some differences in the look between an NTSC and PAL TV/signal. If somebody made a filter/"shader" for NTSC, it seems like a minor addition (for the ones who know this stuff) to make a PAL one as well. I've looked all over the options/menus without finding any mention of PAL except for the aspect ratio.
So I'm forced to emulate my PAL games with the NTSC composite filter and "pretend" to myself that it's a PAL filter, but deep down, I know it's NTSC, and it bothers me a lot.