I lost 99 humanity and over 30 million souls on Manus. I was trying to pick up my blood spot but I kept circling around it. Didn't equip my Ring of Sacrifice, even though I HAD ONE, I thought about it and said to myself "I don't need it, I'm a boss." Yep...I was mad. I took Manus too lightly and paid for it. I was playing with my Dex PVP build at 125 on NG+ as Ciaran, with her full armor upgraded and the Gold Tracer as well. I was really mad but I took a deep breath and said "It happens, this is Dark Souls, you will die."
So how about you guys? I've had dumb deaths as well where I just walk off the edge becaus I wasn't paying attention and then did it again and lost everything. Haha, rule #1, pay attention in this game. Haha.