I close sites that take too long to load.
A lot of American news sites suffer particularly badly, for instance. The second that tab starts slowing up and affecting the others, I've lost interest in it.
I mean, I kind of get you using a lot of CPU if you making live dynamic heatmaps, or I've asked to load a page with a thousand products and images on it, or things like that.
But a simple news story should load as fast as BBC News articles load, whether they have ads or not.
I feel absolutely no guilt about blocking ads. I have run ad-supported websites myself. You only make a pittance - it's really not a viable income stream for 99% of sites at all - and it annoys everyone.
And, as far as I'm concerned, loading third-party code from that third-party's URL and blindly executing it for all your visitors is tantamount to a virus, and certainly an easy avenue for someone to compromise your viewer's or your website in some fashion.
Just today, I went on the TFL site to plan a train journey on a smartphone. Four times I went on, and it worked fine. The fifth time, there was some different ad at the bottom which decided that every time I was going to click on the "Starting station" textbox, it would try to invoke some kind of popup (which Chrome blocked) and thus stop the keyboard appearing. So I literally couldn't type into the box at all after a dozen or so tries. Reloaded. Got the same ad. Same thing. Reloaded a couple of more times, got a different ad, no more popups, and it started working normally again.
That ad could easily have cost you money, TFL. Or done something even more nefarious.