It's amazing to see the amount of people in this post that don't click ads. I really try to avoid to click them, I quite often open an incognito window to search for product I've just seen in an ad (I'm sure Google will find a way to figure out that an incognito user with the same IP as me is... me, but it feels better to try).
But I do click ads in my work, if the top (ad) link on Google is something relevant I might click it if I don't care for the company. I try to avoid clicking links for companies I really like since I work in a very ad heavy industry and know how much CPC can cost.
Me neither, but marketing is significantly about awareness, not just the clicks.
If you've seen it, it is at some level "in you", and the brand has (fractionally) been built.
I know this doesn't apply to all ads by any means, but it's important to remember that advertising also works this way.