Star Trek: Enterprise
A roundly panned series that was cancelled early on, instead of being allowed to achieve the "traditional" seven seasons that every Star Trek show has done since Star Trek: The Next Generation.
The NX-01 design was roundly criticized for being too much like the TNG-era Akira class starships, instead of the older ships that had been seen from time to time in various Trek shows.
Continuity? What Continuity?
Another point of criticism was that the show did not follow long-established Trek canon; instead making things up as they went along.
Token Black Guy
Ensign Travis Mayweather soon became the series' Token Black Guy; usually not appearing in episodes, or when he did, it was to say a single line or lurk in the background.
The Temporal Cold War
A plotline which never really went anywhere, about unspecified future people trying to alter time by messing with the past.
There were a few good episodes of Enterprise; which were worth watching; they are listed below: