I agree that Tanks are not the boss, but it's not a one-wat street of "just pull" either. People should listen to the Tank too.
Back in Heavensward I decided to level Gladiator/Paladin, as I wanted a change. Rocky start, but I had friends guiding me on how to tank. When I reached 60 I started gearing up slowly. The Antitower just go released that week and I had my tank on the minimum itemlevel to enter, obviously I did so. Queue instapopped and I got in. I said I was new to the dungeons and still new to tanking. The small pulls that I had to do first were okay. First boss went smooth. Now, the hiccups started when the 2nd part of the dungeon came. Because it was my first time in that dungeon, I had no idea what to expect, so I just pulled pack per pack. Both DPSs ran out in front and pulled the rest. I managed to get 'em, but I took way too much damage from everything. This resulted in the Healer getting annoyed with me, told me to "properly" tank, even though I used cooldowns. Second wall-to-wall pull same story. After that I asked them to not pull in advance as 1) I wasn't comfortable with it and 2) I knew my gear sucked as I was minimum ilvl. Second boss down, we continued.
Now, I thought that they'd understand my situation and be fine with it. Boy, was I wrong. They kept pulling everything in front of me. I did take the aggro off 'em. But I died on the spot. The incoming damage was way too high for the Healer to handle. This happened during the last bit of the dungeon as well. In the end, they kicked me just before the final boss.
My point being: If a Tank says "I can't handle x or y pulls" then it might be better to listen to them. This Healer thought he'd be good enough to heal me up, but in reality he couldn't. Simply because my gear wasn't what he expected, probably slightly undergeared too. In the end, this experience has ruined my will to Tank. I still play them every now and then and to level them to the new cap, but that's about it. Easy though tanking may be, it's still all about numbers and if you don't meet the required numbers for a large pull, it'll only cost more time in the end.