Quite often:

• To support the site the ad is placed on
• To cost money to the ad's sponsor if I don't like them

Willingly, maybe 4 years ago.

Sometimes I click on ads for mobile games if I think they actually look fun. They just redirect straight into the app store so there's not much chance of anything bad happening

I’ve been on the internet since before it had ads and have never once intentionally clicked on one. These days I always have at least one ad blocker running, so I never see them.

I sometimes click on Instagram-Ads because some of them are so unhinged that I have to find out what they are about?

I don't remember ever clicking an ad. I probably have, but I don't remember ever doing it.

I pay for as much content as I can, to avoid that vomit.