Simple: some things are more important.
Like with most things it comes down to values - I value being happy, but did I value it more than say, getting good marks on my exam? No? So I studied instead of watching movies.
Besides, I can always watch all the movies I want now exams are over. Smaller cost, same benefit, so that's what I'm doing.
Think of it like insurance - if I go for all the happiness now, I run the risk of not being able to be happy later. So I spend some time not being happy while I minimize my future risks, then if I want to say, spend several days straight playing Skyrim, there's nothing stopping me.
Like with most things it comes down to values - I value being happy, but did I value it more than say, getting good marks on my exam? No? So I studied instead of watching movies.
Besides, I can always watch all the movies I want now exams are over. Smaller cost, same benefit, so that's what I'm doing.
Think of it like insurance - if I go for all the happiness now, I run the risk of not being able to be happy later. So I spend some time not being happy while I minimize my future risks, then if I want to say, spend several days straight playing Skyrim, there's nothing stopping me.