Board Thread:Lore/@comment-97.125.181.26-20150622022353/@comment-26149161-20150622135354

Elestan Larcalaite wrote: Actually King Thingol Greymantle of Doriath got the Silmaril from Beren as a brideprice for his daughter Luthien and asked one of the two greatest dwarven smiths of all time, Telchar to put it into the Nauglamir, the necklace of the dwarves. But the dwarves wanted the Silmaril, so they kept it, so the elves hunted them all down except for one, which managed to escape and tell the King of Nogrod a slightly exxagerated story of what happened to make it seem like the elves' fault, so he sent a great force of angry dwarves to attack Doriath. Many elves and dwarves were killed in the process, as well as Thingol. The dwarves stole the Nauglamir with the Silmaril in it and went back to Nogrod, happy about the massacre that they caused. After the departure of Melian, Beren Encalmion killed them all with his army of Laiquendi.

That is the main reason why elves and dwarves hate each other most of the time. That is one reason. The dwarves used the fact that the Nauglamir was theirs to try to get the silmaril. They are kind of like Goblins in Harry Potter.

When the first dwarves appeared, the Petty-Dwarves, the Sindar hunted them for fun. When the "Real" dwarves came, they explained that they were not animals.

The Elves blamed the Dwarves greed as the cause of the Balrogs awakening.

From Ask About Middle-earth (GREAT reference)

Philosophical Predisposition: It’s said that the elves and the dwarves are predisposed to dislike each other because of a conflict in their origins. The elves were always meant to be the Firstborn, but the dwarves were (kind of) created first. If anything this would be a subconscious/unrecognized factor in their relations.