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.