FCP sometimes hesitates when importing

This ever happen to anyone else? I drag files to an event in FCP and it takes a while before progress is actually made. It stays at 0% for a while and eventually it starts moving. Sometimes I can goad it into starting by hitting the pause and play buttons that are to the right of the bars. It's not like the drive it's importing from is busy with something else, I can find no reason for it.  This seems to happen randomly and it's been doing this forever, over multiple revisions of FCP, multiple OSes, and multiple computers. It's just part of the FCP experience but I've never seen anyone else mention it. Also I import everything by drag and drop, never any other way because those ways are more cumbersome.