Dealing With Failure

I've detailed elsewhere my futile efforts to learn Thai (One Guy's Effort To Learn Thai In 14 Years), so I won't repeat the sad tale here. Suffice it to say that years and dollars spent have yielded little in the way of results.

I've resigned myself to the fact that I'll never be able to communicate in Thai, but the nagging feelings of guilt and shame over this are becoming increasingly difficult to handle. How could I have tried so hard and failed so miserably at something that I wanted so much?

I'm sure there are others in the same boat. How do you rationalize or otherwise deal with your failure?