Actually the challenges that I hate are those that replacements of the challenge cards. when a threat to overcome is determined by a dice roll. The one that I hate the most is Wake The Dead That causes you to fight tremendously heavily armored opponents. I mean how many people have their runners wielding enough steel (Firepower) to deal with a 3/4 (A6) bloated zombie, a 3/4 (A5) zombie, or a 3/4 (A4) ghoul multiple times?
This may not fall neatly in to the "Challenge" category asked for, but I think that it fits.
These messages were posted a long time ago on a mailing list far, far away. The copyright to their contents probably lies with the original authors of the individual messages, but since they were published in an electronic forum that anyone could subscribe to, and the logs were available to subscribers and most likely non-subscribers as well, it's felt that re-publishing them here is a kind of public service.