I, myself am content. I don't believe happiness is a sustainable emotion, but being content and satisfied is. As far as being miserable, yes, it is very easy to be miserable. Some problems in your life just can not be ignored, especially if it is financial or illness.
Up until very recently, we didn't have money to make ends meet. And I'm not talking about debt, I'm talking about food, utilities, car insurance, etc. Everyday living expenses. (We own our home and vehicles out right) So I have alot of empathy for people who are miserable because they are about to lose their homes, can't make ends meet, have severe health problems that will never get any better. It's hard to be happy in that kind of situation.
I don't have empathy or sympathy for people like Christina Onassis (yes, I know she's dead) who had all the money in the world and nothing could make her happy. When you can pay your bills, it's a whole lot easier to be content with your life. JMHO.