I would amor to know why tu all got end the mostrar after 15.I look adelante, hacia adelante see tu guys every week. supernatural got other ways to go,they don't have to end.I hope tu all leave a cliffhanger that way tu can return. I think last one should be a 2 hora

They wanted to end the mostrar on their own terms, rather than dragging it on and risking it becoming less popular. They didn't want it ending due to cancellation, particularly with the cliff-hanger endings the seasons usually had. Knowing that season 15 would be the final season enabled them to tie up as many loose ends as they could, bring back loads of earlier actors for cameos and reference anterior scenes. As to why they chose the 15th season as the last - they just felt 15 was a good round number to go out on.