With the right page tagging, people can pretty well search for whatever they want rather than having to passively wait for an ad to pique their interest or show them what's out there. It'd also be quite easy to just create whole sites dedicated to nothing but ads that someone could leisurely troll for entertainment like Trailer Station.
The clutter of obligatory ads in spaces that would otherwise be comfortable white space that people tend to ignore becoming things they want to ignore seems counter productive. It most likely just weakens a person's enjoyment of sites they regularly visit by showing them things that, if they were interested in, they'd probably be specifically looking for them or hearing about them from sources other than ads (newsgroups, product reviews, etc).
Plus with the popularity of pop-up (and other) ads actually being schemes for virus and malware delivery or the ads displaying generic ad redirect namespaces rather than an expected official source of something they're interested in, a bit of paranoia is understandable.
Not to mention how advertising firms can just get lazy and plaster nuisances everywhere rather than make something people would seek out. Let's look at the example of the Old Spice Guy replies on YouTube. Entertainment becoming viral as a means to advertise a product. People sought out these ads having either heard about it from someone else or seeing these videos rake in popularity while randomly seeking entertainment.
Ad blocking is not to blame here, people just want to restore comfort and reduce the clutter of the sites they enjoy. Ads could be bringing people to them rather than just wasting space and hoping to get someone to click an ad that was lucky enough to bypass the developed filters we have on both psychological and software for dealing with a nuisance.
