The original Teen Titans cartoon ended after the fifth season. I believe this was in 2008 - long before I even knew it existed. When I began watching it, I didn't see the episodes in order, so a lot of the fine points of the story arcs were lost on me. Also, I liked Terra and found the emotional punishment she was put through pretty effective. The last episode featured a version of her apparently lacking powers and memories of her time as a Titan, and was a pretty poignant end.
In 2013, a reboot called Teen Titans Go was launched. It has a simplified art style and focusses more on comedy than on action or emotion. The upshot of this is that the characters from the original show are more or less wrecked. It's good for an occasional giggle, but if you were a fan of the old show for more than the voice actors (who have stayed on), you're quite likely to be disappointed.