I've been blocking ads for so long that actually seeing them feels perverse
I use ad blockers and open source privacy focused software whenever I can but occasionally I have to use computers that don't belong to me or an older phone where my usual applications aren't installed and seeing all the advertisements just feels dirty and dystopian.
I think the worst ads are the text to speech ones that say "Download this app today". The unblinking energenic people saying you can make a living at home are probably a close second.
The worst ones I've ever seen by far are ads for mobile games. Some, if not the majority, are full of fetish content, gore and other gross and disturbing stuff just for the shock value; most of the "gameplay" that's shown has nothing to to with the actual game.
Some ads have real people in them act out what (supposedly) happens in-game, those are almost worth watching for their trash value.
Those ads bother me more than most because It's entirely false advertising. Nothing shown in those ads for the most part reflects the actual gameplay in any way shape or form.
There was somebody who actually released a mobile game that has all of like the fake game mechanics from all the advertisements that you see on those ads and it's awful but really funny lol