because the blue or color xenon is not available on e90, so it's scarcity. That means ppl wants it, but bmw cannot satisfy their want. so ppl who wants is but they cannot, the only thing they can do is telling ppl what them have is the best, any others are bad, cheap, rice, etc. such as "mine is better than yours, no matter what you say, 100x better than yours!" so many "kids" here... meaning less.
please go back to school to learn econ, if any of you major on econ, i feel sorry for your professor.