Updated: Aug 19, 2020
"A long term investment is a short term investment that failed".
Be a long term investor the right way. Don't be a "long-term" investor by holding onto an investment that has gone so far south (both price and fundamentals) that at this point, whether you sell or not, it doesn't really matter.
We can't have a 100% hit rate all the time. Even Warren Buffett had misses throughout his journey, most recently in the airlines. To be fair, he really did walk the walk, and those misses were few and far between. Another thing that set him apart was the action taken when there was a fundamental shift in his investment thesis.
Also don't hang on just for the sake of being "long-term", if there are red flags or a fundamental shift in the business (in the opposite, not so good direction), its time to take a second look at the company and act. Don't get married to your initial thesis.
On the other hand, if the business shifts in the positive direction, buckle up and hang on for the ride. Who knew a DVD rental company could become a global streaming giant, a online bookstore could be a top cloud provider, a social media platform could upend the advertisement industry.
Find good businesses you like and understand, and enjoy the ride.
As always, "Come for the laughs, stay for the fun times".