So what's the difference between yellow numbers and red numbers?

qm44

Maybe I'm just a little dumb, but what is the difference between the two? I see people talk about it but never an explanation as to what they are or why you would prefer one over the other.

Demonzfyre

Yellow numbers are critical hits. Red number usually come from an ability effect like energy damage or damage over time debuffs. For instance, red numbers resulting from hits from Nightcrawler are from his deep would kit ability.