Bubble Hearth

Bubble Hearth (aka bubble-hearth) was formerly a Paladin-trick used to teleport away from nearly any threat in the game. It was performed by casting Divine Shield and then immediately Hearthstone, working because the duration of Divine Shield (12 seconds) overlapped the Hearthstone's cast time (10 seconds). Although very useful, it was generally viewed as a cowardly act and those who used it were often mocked for doing so.

Of course, this tactic had to be used when necessary, such as when a roaming paladin found himself unfairly situated against multiple foes and did not stand any chance of emerging victorious. In such situations, the bubble heart was more of a smart move than a cowardly one.

The only ways to prevent it after the paladin had cast Divine Shield was a Priest's Mass Dispel spell or a Warrior's Shattering Throw ability.

In-game references
It is unknown if Blizzard planned the bubble heart to be a paladin-tactic, although it's likely that it's existence was merely a coincidence. Still, Blizzard allowed the bubble heart to exist for 6 years before they removed it.
 * If the player equips an Argent War Horn and uses it, a paladin from the Argent Dawn will appear, fight for 30 seconds, and then despawn by the humorous method of Bubble Hearthing.
 * A fortune by Sayge tells: "Divine Shields and Hearthstones do not make a hero heroic."

Other
There is even a song made by players relating to this act:


 * "I'm a little paladin, short and stout.
 * Here's my hammer and here's my trusty mount.
 * When I get in trouble I scream and shout,
 * then I bubble and hearthstone out!"

Cataclysm
Starting with Patch 4.0.1, the duration of Divine Shield was reduced to 8 seconds, whereas the casting time of Hearthstone remains at its previous duration of 10 seconds, making the Bubble Hearth impossible.

However, there remains a way to use this tactic: by wearing 4 pieces of the Tier 7 Protection Set, you can negate the nerf and still make a glorious exit.

Another solution is The Last Relic of Argus, an item from archaeology. Having a cast time of 5 seconds, it can effectively replace the hearthstone as a teleportation item. The only downside is that it has a 12 hours cooldown.