Millennials get somewhat of a bad wrap. They get crapped on for being "entitled." I personally think entitlement is a human trait generally, and the Baby Boom generation actually is more entitled than Millennials are.
However, there is a trait that I think is unique to Millennials. Millennials tend to get very frustrated, angry, and quickly disillusioned if they don't think they have what they deem ideal conditions to succeed. They are pretty soft, quick to claim things are "unfair," and don't handle adversity well. I don't think previous generations when they were 18-35 showed those characteristics as much as Millennials do. And all of this makes sense, because Millennials were the first generation that truly had "self-esteem" parenting (you are special, all that matters is how you feel about yourself, etc.).
However, if you want to complain about Millennials (and I do), you have to at least be consistent/fair and complain about Baby Boomers. Baby Boomers have all sorts of unsavory traits about them that generations previous to them do not, and you also can't forget the fact that Baby Boomers raised Millennials.