"There are five dangerous traits of a general:
He who is reckless can be killed.
He who is cowardly can be captured.
He who is quick tempered can be insulted.
He who is moral can be shamed.
He who is fond of the people can be worried." Sun Tzu
Does it surprise anyone that being reckless can get you into a lot of trouble? So the idea seems simple. However, if you see this principle in practice, recklessness isn't a rarity. In fact, it seems to be a part of life.
The reason why recklessness is a part of life is because emotions are a part of life. Recklessness isn't a rarity because emotional self-control isn't a rarity.
Strong emotions, positive or negative, skew the way we make our decisions. Depending on our moods, we might not be aware of how they affect us. Depending on what just happened prior, we might not be aware of how that motivates or discourages us in our current decision making. Depending on deeply loved or hated the person saying something is, we might not be aware of how our feelings for that person cloud our perception of his or her words.
All the above are examples of recklessness because in a different scenario, our perception and thus our decisions would probably change. If our decision changes, yet the situation itself didn't change, then the difference -- and hence, the problem -- lies within us. That difference is a problem because we are not rigorous enough in our assessment of the world and thus not being fair to how we treat the people around us.
Sun Tzu goes a step further: those who are reckless can be killed. This is true in war and in violent conditions, but in the everyday where killings don't normally take place, they are terminated, rejected, or excluded.
Those who terminate, reject, or exclude are sometimes completely neutral. They simply don't have an interest in either our success or failure because they act in self-interest, which doesn't always align with ours. So they aren't necessarily our enemies when they act they way they do. Where they do harm is when their act is done in cold analysis without a trace of empathy, and they would do so even if it merely gives them some small advantage.
Therefore, when people act recklessly, they open themselves up to others exploiting their clear mistake, or at the very least, cause others to change their minds.
In my experience, recklessness is predominately a matter of maturity. It is an act I see much too often in young people. However, I believe this is perfectly natural. It is perfectly natural that young people act recklessly when they are not mature yet. Older people tend to get upset with young people for making dumb mistakes, but they conveniently forget how they first started out. They, too, needed time to mature and had their share of dumb mistakes. It is also unfair and unreasonable to expect children to act like adults -- especially when the adults themselves aren't exactly role models.
Recklessness can be controlled through controlling your emotions. Impatience, lack of empathy, and reacting in an extreme manner are common culprits.
One good way you can become proficient at controlling your emotions is through consistent practice in tough situations. Develop for yourself a sort of personal training program that involves taking on moments that would leave you feeling impatient, sounding angry, or doing something mean.
When in doubt, don't say or do anything, but if you must say or do something, make them kind words or actions.
I would be reckless to not include another culprit: ego. Sometimes decisions are made that won't help the situation except to stroke the ego, which ultimately helps no one, even the person being stroked. Ego is also synonymous with greed and selfishness. Others might use this to their advantage by baiting a person who is egoistical, greedy, or selfish since he or she is quite predictable in behavior.
The opposite of recklessness is prudence. Prudence can be achieved by examining each situation carefully before taking action. You can visualize taking an object and analyzing every aspect of that object. You are critiquing without being critical. This is what you can do whenever you encounter a person or scenario in life. No one can take advantage of you when you do this because a proper decision can be defended in the highest courts and on the front page of the Wall Street Journal or the New York Times.