Getting overconfident

Today was another outing with my brother, and I used the opportunity to practice playing the deep inside line on the house shot. By the third game, playing in around 31, I took a 270 possibility into the 10th frame. I got overconfident, however, and left a “fast 8” (the 4-7). I picked up the spare, and the game should’ve still been in the 240s, but I threw the fill ball in the ditch for a 238. OUCH!