Principle of Least Surprise
One of the things I love about Ruby is that it tends to follow the principle of least surprise; things just work the way you would expect them to, with precious few exceptions (cough cough inject cough). Horray for intuitiveness.
On the other hand, I've become so spoiled by The Principle that willful violations stand out like the sober guy at the all-inclusive beach resort. I know I'm being a nitpicky ass here, but this Rails bug^H^H^H ticket makes me kinda ill. Funny, because in my previous life as a Java/PHP developer, I wouldn't have even batted an eyelash at it.