Source Code (spoiler ahead!) had a good take: an agency tasked with investigating & fixing atrocities thru time travel succeeds, leaving a timeline where the agency has nothing to fix and thus faces closing for being merely a lunatic’s dream.
Source Code was a really fascinating movie.
I read that the most “realistic” time travel movie, according to “scientists” is “The Time Traveller’s Wife”.
For me, that one is a serious tear jerker, and probably the best “time travel” movie ever made. FWIW, it’s my favorite science fiction sub-genre.