2 issues. Inconsistent quality control of ads. In some places ads have content that would be banned in the actual YouTube videos. There’s also inconsistent quantity of ads. You can have 5 second or 14.5 second unskippable ads with the timer for determining if an ad is unskipple getting longer and longer. I’ve also seen a 10 minute video with 3 double ad stops and it’s all creeping up with them even now not showing the timer for ads in the Android app. They were fine when they started ads but it’s getting worse.
The longest ad I’ve see on YouTube was about 7 years ago and I watched the whole ad because someone paid for the entire Michael Jackson’s Thriller video as an ad.