Always, ALWAYS bitchy. The type of player where you bring something match relevant up, and is always the first one to say "Stop typing and play." Farms your lane and take CS about 60% of the time. Don't take support items about 80% of the time. Does almost everything they can to steal kills from you. But that's what you tend to do as a _mid laner._
ADC's are well known for their god complex, but Lux support mains seem to take that complex, quadruple it and assume the weight of the world is on their shoulders without giving anyone else a chance to play right.