Excessive use of Guava's functional programming

https://code.google.com/p/guava-libraries/wiki/FunctionalExplained

Excellent to my mind ! Common sense should win functional craziness.

Excessive use of Guava's functional programming idioms can lead to verbose, confusing, unreadable, and inefficient code. These are by far the most easily (and most commonly) abused parts of Guava, and when you go to preposterous lengths to make your code "a one-liner," the Guava team weeps.

Imperative code should be your default, your first choice as of Java 7.