A kangaroo is not usually an aggressive creature. In fact, if it senses that you have seen it, it will do its best to hop away from you. There may be moments when you would do something to anger the kangaroo and that is the time when it would protect itself. It can also become more protective if it has a joey (or two) in its pouch. It is best to steer clear from rampaging kangaroos.
There are still other things that you can do so that you will not get attacked. First, make sure that you will not look at the kangaroo straight in the eye. This might provoke the kangaroo. You should also protect your neck and other vulnerable parts of your body. Lastly, try to get away from the kangaroo as fast as you can.