Once you've figured out that quality and strength of character is the single determining goal that should structure a life, a complicated net of paths to achieving that goal is laid out for you. Choices must be made all the time, and there are plenty ways of going wrong.
Let's start with feelings. Some people get emotional about the wrong sort of thing all the time; take for instance those who are unduly concerned with the opinions of others. They will be angry at you if on some occasion you spoil the effect they intended to make; they'll become nervous when they're running into a situation where they suspect they look bad; they are elated and inordinately cheerful when they've just landed a hit with their audience.
When people acquire such a disposition, then it isn't just their feelings which harden into a pattern. Actions follow: they will begin to do foolish things just to make a good impression, refrain from doing sensible things if there isn't an effect to make, they will make it a priority to seek occasions where they're seen in a positive light, ignoring other options which might have been better for them, all things considered. And finally, their views will be distorted: they will form opinions and beliefs, especially on what is good and what is bad for them, which are above all influenced by how well people think of them, and not by what is actually the case.
Just as the opinion of others can play this role of a false good, other things might as well. Some people get emotional whenever wealth and money are concerned, some when their personal wellness is touched, when physical comfort and the pleasantness of their surroundings is affected. As with those who are fixated on the opinions of others, those who make money or well-being the central concern of their lives are not just disposed to slide into progressively stronger feelings about them; they will also quickly have their actions, views and with them their long-term goals and projects influenced and finally dominated by them. In the end, there is a good chance that they'll have spent their whole lives chasing a false good, something that, as they are likely to find out, is not, and never has been, worth it.
Chasing false goods, however, is only one way of going wrong. Another one is to develop an aversion. Bodily pain, for instance, or being in a crowd with other people, is something that occurs from time to time in anybody's life. But if you've got an aversion against that sort of thing, then you will try to avoid it at all costs, and whenever possible. In the end, even having to face a single instance begins to look unbearable to you. In reality, you can at times avoid unpleasant or painful experiences, but you can't avoid them altogether, and avoiding is not always among the sensible options. Those who drift into strong feelings whenever there's even a small probability that they will have painful or unpleasant experiences, those who, that is, are subject to aversions of this sort, display the same pattern as those who chase false goods — they're just not chasing, but fleeing, and it's not false goods, but false evils which they are obsessed with. And again, it isn't just their feelings which become ingrained as a pattern: in their views and actions they will show the same unbecoming tendencies, they will form incorrect beliefs and act insensibly whenever their false evil is at the horizon.
(Especially if you think of more specific aversions, for instance to certain animals such as spiders, there are of course psychological or psychoanalytical explanations for these phenomena. After all, psychology includes exactly that: the study of these phenomena, and possible therapies. In addition, however, to what the best psychological theories take them to be, we always have to ask ourselves what stance to take to them in the first place: we should find an evaluative attitude that is based on reflection, and related to what we think is good or bad for us. If we don't, how could we ever know which of them to fight and which to tolerate? So, are we to simply accept them into our psyche? Perhaps even cite, as an excuse, certain reductionist theories which tell us that everything is hard-wired into our genes anyway, or that our childhood experiences will determine how we feel and what we do, whether we recognize it or not? Are we going to settle for an 'I will try my best, sometimes, perhaps'-kind of stance? Or shall we rather think it through what exactly the impact of such personality attributes on our own lives would be, and work hard to eliminate them, as a priority, exactly to the extent we take them to be harmful — even if that means to engage in a life-long battle with ourselves?)
So far we've only looked at getting emotional about the wrong sort of thing. There is another way to go wrong in your feelings, actions and views: you can become disposed to getting emotional about a range of different things, but always with the same emotion. This is what's called a proclivity: a habit of falling into the same sort of emotion all over, whether it's appropriate or not. Examples are timidity, or enviousness. If anything can frighten you (including a lot of things that most people wouldn't be afraid of), or if everything you see in use or in possession of someone else inflames your desire, then you're certainly not on a good path. It's this time not so much a wrong evaluation, taking a false good (or a false evil) as something that is genuinely good (or bad). It's rather a habit of falling into an emotion type too quickly and too easily, a proneness to fall for them on too many occasions, most of the times inadequately.
All sorts of habits (in feelings, actions, and in views) are in fact rooted in repetition, and learning: learning proceeds often by repeating some behavior. Habits thus originate in oft-repeated behavior which has transformed into dispositions to act the same way again and again. They've become traits of your personality, and so form an important aspect of what you are. And once they are in place, in many situations feelings, views and actions flow in a natural and often involuntary way from them. When they are thus ingrained, it is not easy to even recognize them; and you cannot change them immediately at will; but you can change them by building up alternative habits from more appropriate responses, which look to the real value of things. Of course, that requires patience and will. But it can be done.
And because patience and determination themselves are qualities of character, from a lack of them in forming good habits comes yet another way of going wrong: your good habits can be unstable, not yet capable of persisting through unfavorable circumstances, of remaining constant over a broad range of situations. That's what is called an infirmity of character: when a habit isn't hardened enough, and there are relapses. Infirmities are both a good sign and a bad one: for they show that you are on the right path, but they also indicate that you must push on and get further on it. Take care.