Expression trees in C# is also an example of this. I have 10+ years experience (and consider myself highly proficient) in C#, but my interaction with expressio

Expression trees in C# is also an example of this. I have 10+ years experience (and consider myself highly proficient) in C#, but my interaction with expression trees is mere hours where I've only once or twice needed to solve a very specific small problem which I could do with a small tweak to code copied from Stack Overflow.