In one sentence, describe what the following article is about:

Some dictionaries say the word stems from the word crab and the word cur, which meant dog or a "disagreeable person" in Gaelic. Some of the definitions of curmudgeon are not positive. For example, a curmudgeon is defined at times as a "crusty, ill-tempered" old man. In popular culture, curmudgeons are typically older men with grouchy attitudes. However, not all definitions of the word are negative. For example, an alternative definition says curmudgeons are people with stubborn ideas or opinions. This might be laughed at by some, but it can be a strength at times. It's certainly necessary for any institution or society to have people willing to say what no one else will. Studies show that curmudgeons are more likely to be males and over the age of 70 - although they do exist among all demographics. There are physiological changes that occur with age and that can cause a worsening of mood. Sometimes men are really experiencing physical symptoms like declining testosterone levels that make them grumpier. If you feel like a curmudgeon, but don't want to be one, see a doctor. Maybe there is a medical issue that a doctor can address. If you are feeling depressed on a constant basis, that's not a good place to be. It's different if you are choosing to be a curmudgeon and are happy in that state (even if you don't show it). But if you are suffering signs of clinical depression, contact a doctor or therapist. There are many resources available to help you. Start paying attention, and you will see curmudgeons in public life everywhere. They are a common character in movies and politics, for starters. Supreme Court Justice Antonin Scalia is sometimes considered a curmudgeon. This is because he will often play the iconoclast, and his contrary opinions are often filled with words that are designed to have an attention-getting flair. However, he has an underlying mission and stays true to his stated values - he wants to make a point about the problems with the majority decision. Curmudgeons consider themselves lonely arbiters of common sense and sometimes they are right. Clint Eastwood in the movie "Gran Torino" is a curmudgeon. "Get off my lawn," is his famous catchphrase. Walter Matthau is a curmudgeon in the movie "Grumpy Old Men." Bill Murray in the movie "St. Vincent". Dana Carvey's character "Grumpy Old Man" on Saturday Night Live is a curmudgeon.

Summary:
Figure out the kind of curmudgeon you are emulating. Realize that sometimes grumpiness is camouflaging a medical issue. Study famous curmudgeons to get a sense of how to do it with style.