Conclude your science. Don’t summarise it.
A summary that merely repeats previous material is prohibited for the journal Nature and would be be edited out. Other journals are less strict, but perhaps they should follow Nature’s lead and recommend instead that the conclusion offer something new to the reader. This is often easier said than done. Scientists default toward endings that are typically cliche, uncompelling, or just tail off. Let’s look to factual but more expressive forms of writing, such as long-form journalism and narrative non-fiction, for examples of better endings that could be applied to scientific papers and talks.
Journalists arguably have a little more freedom than scientists in how they word the ending of a piece. A memorable quote or a clever joke, perfect fodder for a popular article, would be out of place in a scientific article. Yet there are several forms of conclusion that we could borrow from journalists to provide a more engaging ending. I’ll borrow my examples primarily from The Atlantic, but any decent popular publication can help.