Hiya,
This article is not necessarily intended as criticism, but since many negative articles have already appeared on the forum …
Tanking is not difficult, but can quickly become a nightmare for both the tank and the healer due to bad behavior or ignorance. Warrior tanks in particular have been under fire since the launch of wow classic. Many players don’t seem to know the difference between threat and damage. A warrior tank has to do almost all its capabilities with rage, and at the start of a pull or run that counter is on zero. By doing damage and getting damage, a warrior builds his rage and can start using his abilities. If a fight stops, the rage will gradually disappear.
With the pull of a mob or mob pack it usually goes wrong because dps’n get involved in the fight much too quickly. In a defensive stance, a warrior has almost no options to taunt mobs on a distsance. I use my bow to get the mob to me. Now that the mob (s) are in front of me, I still have no real control over it, my rage is still zero. By systematically making hits and getting hits, my rage will rise and I can start using sunder armor. Sunder armor does no damage, but reduces the armor content of the mob by 90 and it can stack up 5x. It does give the tank a lot of treat on the mob. From now on, it is actually safe to start with dp’s with damage. Ofcourse you have more spells and techniques to build damage vs aggro, learn to use them well. If a warrior changes his stances, he has lost his rage, keep that in mind as a tank.
Threat works based on a formula, You hit a mob with 100 damage and you generate 100 threat. Some spells or options have a multiplyer and regenerate more threat than damage. If I do 50 damage with my bow and a mage does a 150 bolt frostbolt, I run behind 100 threat and the mage will pick up the mob. Healers, too, can pull aggro through healingspells because these too are converted into threats to the mob. This theory is really just the basis, there are loads of articles and videos that go much deeper into these things. Try to remember and avoid not going over the tank in terms of aggro and that limit is different for every tank.
So if next time a Warrior tank is asked to give him the opportunity to build up aggro, respect this. Let the tank pull and stay behind untill the agro is on the tank. As a tank I know what is expected of me, if you can keep control as a tank it is also more pleasant for the healer and for the mood in a group. Suppose it goes wrong once in a while and you get mobs on your neck as a healer or dps, then don’t run around like a possessed person or go fear the mobs, which can attract even more mobs. Stop your damage and bring the mob to the tank. As a tank I will always try to protect my healer from damage and keep an eye on his mana. If you die as a dps, don’t start nagging at the tank or even worse the healer, only if you as a dps pay as many repairs as I do, you can come forward and complain 
As a tank, try to inform your fellow players with the order of attacks: Skull = first, cross = second, moon = polymorph, circle = sap, square = hunter trap, diamond = fear … Dare to give orders to your fellow players and make sure that your battleshout stays up. Are you an experienced melee dps, help your colleague tank by pulling in mobs into his group … IF and I repeat IF he has the pack under control, I myself greatly appreciate this. Hunters and Warlocks, do not use pets that tank or keep them under control. In the dealing of loot, I leave the cloths and leathers for what they are, unless I could sell an item on the AH, the same with weapons, staves are caster weapons unless you can choose it from a quest. It saves you a lot of drama and last but not least, I would like to say that a healer or a tank also needs to complete collection quests and perhaps also do herbalism or mining. This entire article is just a basis for becoming a better tank or for getting a bit of the tanking phenomenon. Try to live with criticism or learn your lessons from it 
Success and have fun