Star Trek: Deep Space Nine (1993-1999)
I came into the show late when it originally aired and only caught a few. I had no idea what was going on and didn't bother to stay with it. Now I wish I had caught the whole thing from the beginning. This was a great show and a breath of fresh air. It made TNG feel cold and impersonal in comparison. The series finale was really bittersweet. This is definitely my favorite series after TOS.