Doctor it hurts when I do this. Well, then don't do that.

From the BBC:

Apple has released official advice for iPhone 4 owners to overcome the problem of the device losing signal when held by the lower left corner.

Steve Jobs responded to a query about the problem from one owner by saying: "Just avoid holding it in that way."

http://news.bbc.co.uk/2/hi/technology/8761240.stm

I have a term for stuff like this: Junk.