Update by @unknown:
Summary:
Villagers should produce anger particles when they are hit by a player, if they are within a village. They currently only do so after opening the trading UI.
Steps to Reproduce:
Find a villager in a valid village
Punch the villager
Open and exit the villagers trading UI
Punch the villager again
Observed Results:
The villager will only produce angry particles when hit if the player has opened the trading UI.
Expected Results:
If the villager is within a valid village, it should always produce angry particles when hit.
Screenshots/Videos attached: Yes
Notes:
Original Description:
The angry villager particle is missing. Can you please bring it back?
Linked issues
Attachments
Comments

Updated description and added example video.
Updated description and added example video.

In an experiment in 1.7.0 using Windows 10 and a third-party NBT editor, I found that when a player enters a village he was not previously in and attacks a villager,
The player is added to the village's Players list if not previously there
The player's S (popularity/reputation) value is decremented by 2 each time he attacks a villager
The attacked villager will display anger particles to the attacking player only, but only if the player has previously opened the villager's trading UI.
Assuming the purpose of the anger particles is to warn the player that he is damaging his reputation with the village, their display should not be conditional on whether the player has opened the trading UI first.

In an experiment in 1.7.0 using Windows 10 and a third-party NBT editor, I found that when a player enters a village he was not previously in and attacks a villager,
The player is added to the village's Players list if not previously there
The player's S (popularity/reputation) value is decremented by 2 each time he attacks a villager
The attacked villager will display anger particles to the attacking player only, but only if the player has previously opened the villager's trading UI.
Assuming the purpose of the anger particles is to warn the player that he is damaging his reputation with the village, their display should not be conditional on whether the player has opened the trading UI first.

Replicated issue in

Replicated issue in