Now a days, I believe there's no point in learning or knowing every aspect of just a single language, when in the real world are a lot of other languages that at some point you're going to use, others are thousands of the already saturated area of Frameworks which some use special way of writing in spite of being the same language. It's simple not useful to know a 100% of pure language or trying to implement something natively just for the fun of it when you have to deal with a dead line and low budget. I don't understand why a lot of people out there try to re-invent the wheel and not to improve it.