Star Trek: enterprise. Probably not the best Trek show but it got dropped right when it had found its stride. Also I enjoyed the temporal war arc, which most trek fans seemed to hate. Would have loved to see the stuff they later revealed in interviews that was planned, like archer himself becoming the suliban leader from the future.
Arguably Enterprise should have ended before certain things happened in the last episode that fans HATED. Or reboot the friggen series and hand wave it away as part of the time cold war.