Out of all 7 Seasons of Buffy yes it was the worst with only a few good episodes or one you have to watch.
Let me think
Buffy vs Dracula - this is a funny episode, plus it's Drac nuff said!
No Place Like Home - we find out what the deal is with Dawn
Fool for Love - great Spike episode with flashbacks and everything plus the chance to see Angelus, Darla, Spike and Drusilla together can't be missed
Into the Woods - Riley leaves yay
Crush - return of Drusilla, Spike admits his feelings to Buffy
The Body - Stunning episode with no music and with some of the most powerful performances by Buffy actors
The Gift - End of the Season, kind of essential if you want to understand Season 6, cool effects and touching scenes.
The rest are pretty missable, Checkpoint and Family are okay but are only really worth it for the last 5 minutes or so.