It all depends on the uploader, I have the ads on my videos all set to skippable by default.

AdBlock is my best friend :p

Highly recommend you download this plugin if you are on a computer/laptop

I forgot YouTube did ads. Occasionally I will watch on a device that doesn't have ad block installed and it's usually the most excruciating 10-30 seconds of my life. Luckily that only happens about once a year.

This mirrors my experience.

At least with TV I can mute, get a snack or tune out (either literally by changing channel, or mentally tune out) but with a video on demand service I clicked with the intention of watching it then and there.

I use AdBlock, so I don't have to worry about it.

Adblock is your friend ...

There are still some skippable.

I noticed a 10 second unskippable advert on youtube the other day, I thought that was great, I wish they were all like that.

Haven't had this problem but most of my youtube time has been through PC (ad block). On my phone they're usually not too annoying.

I always watch ads to support those youtubers making content. Shame on you guys.

Same. I want my views to help them so no issue for me. Besides if it is a long ad I just have multiple windows open and don't "have" to actually watch anything.  I did encounter an hour long ad for a 3 minute video which I found amusing.