Most people probably think that this show is just some silly 90's series. However, it was produced by Josh Whedon who has done some amazing work on other series and in the Marvel Universe. The show Buffy The Vampire Slayer had moments of extreme brilliance, where particular episodes would leave you with your jaw on the floor.
The problem is that the show didn't start to get really good until about season 2 episode 6. Season 1 was very weak overall, but fortunately, the show kept getting better up to the end of season 5.
If you are watching the show for the first time, I recommend watching Season 1 episodes 1, 2, 7 and 12, and Season 2 episodes 1 and 3 and then jump to episode 6. The episodes in-between are semi-lame "Monster of the Week" shows.