If you come from another language, you might be tempted to use the += operator when appending to a string.
Sometimes, you want to initialize a variable to some value only if that variable is equal to nil. If you like to write your methods as short, clean and readable as possible, you can do that task in a single line instead of taking the traditionnal 3 lines approach.
Ruby truly is full of surprises. Until recently I was under the impression that Fixnum objects were like every other objects. A discussion emerging from one of my article made me realize that it was not the case. I then decided to understand once and for all what Fixnums were really made of.