Seth is right though. Chaos only came into being because of the War of Heaven and the psychological and emotional backwash of sentient species, especially those that are more psychically attuned to the Warp like the Eldar and Krorks (original Orks except the average one was basically Primarch tier in terms of size, psychic energy, etc...) fighting the C'tan and Necrons is what caused a backlash to turn it into a daemonic shithole across the galaxy in the Immaterium; before that the Warp was just a realm of psychic energy that the Old Ones would chill in. Its just not negative emotions anyways, its any emotional aspect that powers them; Khorne became what he was because he is the embodiment of war, rage, bloodshed, fury, murder, and violence, Tzneetch from planning, cunning, change, and evolution, etc...