I never minded web ads from The Deck Ad Network because they were always small, not intrusive, and well-designed. They looked nearly identical to the ads you see on the left column of Daring Fireball these days (a small thumbnail + text blurb)
Of course, The Deck is no more, so go figure. Almost all other web ads I cannot stand. They're always in terrible positions, there are too many on a page, they move content around or cover it, and these are just the aesthetic problems. Security/tracking, battery, and browser performance is a whole different beast, and an arguably far more important one.
Even if all ads were to begin behaving, at this point in my life I would still block them. Ad firms / publishers had their chance and they squandered it. Even now, the issues remain and many of them are not cleaning up their act.
Pi-hole for blocking at network level is a great solution.
