Well, you are. No, seriously, this is a typical problem in most cultures around the world. People tell their children (with words and actions) that they are no-good, worthless, useless drains on their parents' happiness, pocketbooks, and patience. Given this scenario, you get a lot of adults who became convinced as children that they were just no good, and they helpfully pass this attitude on to their children. Lovely predicament, eh?
Well, thankfully, they were wrong. Let's take useless first, it's easier. You cannot be classified as useless, because you aren't really supposed to have to make yourself useful. Look at the natural world. What is the use of a tree? Well, it has many uses, but it isn't TRYING to be useful. There's the difference. It's just doing what it wants (or so we assume) and in the process of doing that it does its job in the natural order of things. Despite all the rantings of moralists, you are in the same boat. The only way you are ever going to do an ounce of good in the world is to do what you want. Do what makes you happy, or at least what distracts you from your misery. Important Note: If you have an underdeveloped sense of empathy and enjoy doing things that harm others, ignore this advice and get professional help!
How, you may ask, does doing what you like do any good? Look around you. Look at people who seem to be trying very hard to be useful. Are they really doing good things for people? Or do they make everyone around them miserable with all their moral uppidyness and incessant busy bodying? I suspect it is the latter. The people who really do others some good are the people who are doing what they like and who aren't very interested in being useful. They are usually interesting to be around, because they are doing things that interest them. They are often fun to be around, because they appreciate fun and know how to laugh and not take anything too seriously. They inspire other people to figure out what it is that they want to do by example, thus causing more people to be interested in life and interesting to be around, fun loving, etc.
Out of all the people we meet in life, these people who are doing their own thing are the people who have the most profoundly positive impact on us and thus make our lives richer in the most fundamental, meaningful way. Can you really call that useless? Sure, working in a soup kitchen will feed people, but if you're being a martyr about it because you don't really want to be there, everyone around you will see right through you and hate you for being moralistic and insincere, and you will end up doing more harm than good. So, revel in your perfect uselessness. It's the useful thing to do.
What if everyone in the world just did what they wanted? Would it be anarchy? Well, that starts to get into the subject matter for our eventual companion page, How to Solve All the World's Problems.
If you can overcome the stigma of uselessness, you are halfway to getting over worthlessness. Because worthlessness is often just the moral judgment you place on yourself when you think you are useless. However, worthlessness goes deeper. Worthlessness implies that you don't even have a right to be here. You are not one of the blessed, you are one of the damned.
You see, there are really only two moral beliefs about people, either people are basically good, or they are basically bad. 99.9 percent of the world's population believes that people are basically bad, and that's a problem. If it's true that people are basically bad, then there is no hope for us; democracy is obviously doomed, and a benevolent monarchy is impossible because no basically bad person could stay benevolent once they had all that power.
Are people basically bad? Let's look at the facts. Once again, look at the people around you. Once you get to know them, you realize that:
Everyone on the planet is in exactly the same state of moral worth, because we are all doing the best we can with what we have. Poor upbringings cause many people to not have much to do their best with, but hey, that's life. Criminals believe they are powerless, so breaking the social contract is the only way they think they can get what they need and manage to feel somewhat powerful. People without that hang-up can see that cooperation and respect are really how things get accomplished, but both of these types of people are simply trying to live a fulfilling life using the methods that they think have the best chance of working. So you see, people are basically good. They are all trying to do their best. They often just need some help overcoming inner demons and behavior patterns that aren't really working for them.
Obviously, you are in the same boat. You are doing the best you can with what you have. You are already living the most moral and correct life you know how to live. There is no more that you can do at this moment to be a better person. You are already a good person. You do not have to strive every moment to be better than it is possible for you to be. Smile at yourself. You're OK.
Now, it should be clear that you can improve. Not by beating yourself over the head for bad things you've done; those things couldn't be helped. You were just doing your best with what you had. What you can do is learn where your blind spots are. Watch others. People who at first glance are just plan old bad people are on further investigation suffering from horrendous misconceptions about how the world works. You also have misconceptions about the best way to get what you want. Find those misconceptions and wake up!
But, don't worry if your progress is slow and unsteady. You will make progress, but after all, you can only do the best you can with what you have. (Man, why did we beat this topic's catch phrase into the ground, over and over? Well, we were just doing, you know, that thing we said.)