You should always invest with an end goal in mind. It could be something as long-term as retirement. Or it could be short-term as your kid’s college education.
When picking individual stocks, you could often run into issues where your original thesis proves to be wildly incorrect. Fraud is the most common example.
Investing in stocks is hard. Timing when to buy and sell is more challenging. Turning off the daily gloom and doom news and sticking to your investment plan is more problematic due to many behavioral and psychological challenges.
There is nothing inherently wrong with bad news, but we should be conscious of the world we live in and the media cycle pushing the more sensational story to grab our attention.
The human spirit will grow and make this a better and more efficient place to live than before. If that assumption turns out to be incorrect, we have a lot more to worry about than the value of our stock portfolio.