The article text supplied here contains only website navigation and mailing-list boilerplate, not the body of the piece, so the substance of the story cannot be summarised accurately. The only genuine information available is the headline: that Ben Stiller described a particular cut or edit made to a 2013 project as "the worst decision I ever made" in his career.

Without the full article, the key details — which film the decision related to (2013 being the year Stiller directed and starred in The Secret Life of Walter Mitty), what was cut, and why he regretted it — are not recoverable from the text provided. Summarising further would require inventing claims that are not present in the source.