I usually try to 100% everyone I raid. I want the experience and the general courtesy of giving someone a 10 hour shield. But when half off my army is wiped out while they're beating on your town hall, or your hero picks of my troops one by one while they beat on a wall, or when I cast heal from the magic shop and it does absolutely nothing, I run out of troops before I can finish you off. So for anyone mad when they see me 50-60% them, please understand it's not my intention to do so. Despite many attempts with bug reports and "live support", nothing changes. I know the game is still young but I just wanted to throw that out there. Maybe it will get fixed at some point.
I actually tried to give raiders "free" win, but they still didn't 100% my base so I usually max my defense and make them loose their troops so they have to wait several minutes. This is also good because high level players can just destroy your base without much loss and they always 100% my base.