Pleasure depends on things, happiness does not. As long as we believe that we need things to make us happy, we shall also believe that in their absence we must be miserable. Mind always shapes itself according to it's beliefs. Hence the importance of convincing oneself that one need not be prodded into happiness; that, on the contrary, pleasure is a distraction and a nuisance, for it merely increases the false conviction that one needs to have and do things to be happy, when in reality it is
just the opposite.
But why talk of happiness at all? You do not think of happiness except when you are unhappy. A man who says "Now I am happy" is between two sorrows, past and future. This happiness is mere excitement caused by relief from pain. Real happiness is utterly
un-self-conscious. It is best expressed negatively as: "there is nothing wrong with me, I have nothing to worry about".
Once you have grasped the truth that the world is full of suffering, that to be born is a calamity, you will find the urge and the energy to go beyond. Pleasure puts you to sleep and pain wakes you up. If you do not want to suffer, don't go to sleep. You cannot know yourself through bliss alone, for bliss is your very nature. You must face the opposite, what you are not, to find enlightenment.