A double-edged sword is anything that can have favorable and unfavorable consequences. I pose a list of fundamental double-edged swords to the human condition below.
A double-edged sword doesn’t have to be unfavorable. Making explicit and understanding the nature of these double-edged swords may perhaps help to flavor more of or only the favorable aspect of them.
Here is the list:
“There are two tragedies in life. One is to lose your heart’s desire. The other is to gain it.”George Bernard Shaw, Man and Superman
All achievement stems from desire. But what is all that achievement for once the desire is met and now is no longer treated with the zeal that comes with the newly desired? 
There is no end to desire. A particular want can be satisfied. But never is want itself satisfied.
Desire gives meaning, but it can also cause a meaningless loop—the metaphorical rat race.
Comparison really is an accelerator of improvement. Comparison done bad is the thief of joy.
“Compare yourself to who you were yesterday” has become popular advice that criticizes the notion of comparison with other selves that can cause jealously and hatred and rob us of our joys.
But comparing with oneself doesn’t give much of a broader view of reality that could be ours. It doesn’t give the significant passion one could get by comparing with another for accelerating improvement or changing direction.
Of course, one could also reject the notion of self and that would require no comparison whatsoever.
Fear is sensible when it makes you survive.
Fear is irrational when it clouds reason or the fact that there’s nothing to be afraid about. Or when it stops you for something you’d actually want to metaphorically die for (i.e. something you’d really want to strive for).
Fear saves but also puts one in restricted, at times dull caves.
You can thrive on the fuel created by negative emotions like anger. But all that thriving cannot be sustained on negativity when it inevitably emits unfavorable consequences like burnout.
Anger makes you want to do something, to change what you feel by doing it. But anger changes you first when you allow it to take over yourself.
Anger can make you do great things. Anger can make you do dumb things.
Pleasure feels good. The return to normalcy doesn’t.
Pleasure feels like happiness. But it gives the false illusion of happiness.
“Addictions let you engage in fake play and fake work. Before, you had to go socialize with friends; now, you can just get drunk with a bunch of strangers. Before, you had to go find a mate, create children and raise a family; now, you can just watch a lot of porn. Before, you had to hunt and climb trees to get fruit for a little bit of natural sweetness; now, you can buy all the gelato you want.
The modern struggle is standing up to these weaponized addictions. They give you small doses of pleasure, but they also desensitize you and expose you to the misery of their absence.”Naval Ravikant
Buying stuff fills up our hearts for a moment. But the product once bought almost never offers the same pleasure it did while being bought or while being sought.
Purchase fulfills a desire and makes space for another. And of course with any new purchase comes added weight and space—physical and emotional. It needs a place in the house, it needs a place in the mind. It can breed attachment. It can be a burden.
Habits done well allow for new problems to get attended to rather than the plain-old everyday ones.
Habits don’t require much effort so you can turn your attention to more important or novel things and let routine follow in the background with little or no conscious force.
But habits once fixed require a lot of conscious effort to break.
Most of the while habits form unconsciously. Bad habits can be formed this way. And breaking the chain ain’t easy.
Progress is good. Without it, there is a place for dogma to creep into. Progress improves lives. It creates opportunities and hope.
Progressing into states of power without higher states of wisdom though, can be fatal.
Many of the dangers we face indeed arise from science and technology—but, more fundamentally, because we have become powerful without becoming commensurately wise.Carl Sagan, Pale Blue Dot, 1994
To be wise though, we would still need progress.
 – The passion that comes with a desire is extinguished when the desire is met. This makes the achievement that came due to the passion not as appealing as it had been with the passion that comes with the desire.
“Ultimately, it is the desire, not the desired, that we love.”Friedrich Nietzsche