Once I had some (considerable, 3 months) spare time and decided to fulfill my ambition of writing a chess program. This one would be special - it would work to a strategy, rather than brute force.
3 months later, and having written it first in Java, then C++, then C, I realised that it could never compete with the brute-force millions-of-nodes-per-second crunching machines.
This actually made me become disillusioned with chess as a whole, although the emergence of Rybka has restimulated my interest somewhat.
The idea that strong chess programs mean that AI is on the march is, sorry, laughable.