I know with a lot of things in life if you think too hard or "want" them too badly sometimes the added pressure and stress of that desire can cause you to fail. For example, when I go to the gun range for fun I end up shooting bullseyes like no tomorrow. But when I'm trying to show or impress somebody and really stress the fact that I need to hit the centre of the target, I often miss.

I think a similar logic applies here. If you stress yourself too much by wanting an LD too much, that stress could cause you to fail at having one. But, if you don't worry about it (or in your case, say you don't want one at all), that pressure should be removed. Deep down you still want to have one, and your mind knows this, but it's not relaxed enough to achieve it. When you remove that pressure, you are able to LD. That's just my idea anyways, just based on personal experience not science or anything like that.