Everything in life is a comparison between everything else and if you think about it, we only gauge one thing by how it measures up to another.
Think about good and evil for example – you can’t have one without the other. If everyone in the world were nice, friendly and only acted in good spirit, evil would not exist. But if evil did not exist, then this would not seem “good” and in fact, much lesser flaws and faults among humans would appear to be evil in comparison.
We cannot have happiness without suffering, otherwise again we would not know what happiness was.
This can be useful to consider in every day life as well, because good things tend to come with an opposite force. Or a negative situation.
Drugs, or alcohol are a very simplistic example – if you take the someone positive highs of intoxication then in turn you have to suffer the lows of a hangover or a come down.
If you cannot handle those lows then you should avoid the equivalent highs.
This can be used as a mantra for any other area of life as well – when you undertake something for your own benefit, think about the opposing forces that are involved, the potentially negative outcomes, and take this into account when deciding whether to get involved.