Let me kindly disagree on the readibility. No, not completely: Good code should be readable, and that can be easily achieved with enough comments.
But I consider two kinds of WTF: those where you wonder if the programmer got further than programming 101, and those where you absolutely don't grasp the geniality of the code. Some code can look very strange at first, but is actually a very inventive solution to a hard problem. The second one shouldn't count in the WTF-meter, and can be avoided by comments.
Very readible code can be very, very slow. A less readible solution can give a manyfold improvement in speed. R is a great example of a language where that often is true. One likes to avoid for-loops there as much as possible. In general, I'd consider the fastest code the better code even though it's less readible. That is, if the improvement is substantial off course, and enough comments are inserted to explain what the code does.
Even more, memory management can be crucial in many scientific applications. Code that is very readible, tend to be kind of sloppy in memory usage: there are just more objects created. In quite some cases smart use of memory makes the code again less readible. But if you juggle around gigabytes of DNA sequences for example, memory is a crucial factor. Again, I consider the less memory-intensive code the better code, regardless of readibility.
So yes, readibility is important for good code. I know the adagium of Uwe Liggis : Thinking hurts and computers are cheap. But in my field (statistical genomics), computational times of a week and memory usage of over 40 Gb is not considered abnormal. So an improvement of twice the speed and half the memory is worth a lot more than that extra bit of readibility.