Action are louder than words! But what if there's action and no words, or when there are words but no action? Is it still the same thing? Do you have to say something to really mean it? Isn't your action is already expressing your feelings?
No my dear. Sometimes both things need to be done to have meaning. Words back up your action. A person mighty interpret a "kitchen sink," for instance, different from what you interpret it. Words are a prestige to action. They make action sound better and they are important to use in a conversation and in a relationship. At the end, you don't want the other person to misunderstand your action just because you didn't say what you meant to do.
At times, there are some words that cannot just be said, but it has to be done. Words like "love," "sorry" are important to not only be said but also to be shown.
But never say things if you don't mean it. Just because you were put on the spot, or you didn't want to hurt the other person's feeling that doesn't mean that you should say things to make a conversation because you might end up hurting the other person feelng and driving them away. Always remember to act to what you say, and say what you mean.