Because sometimes, the bug report is more interesting than the actual bug.
Claim that the bug is not a bug at all, but rather an "feature" of the system.
Learn more about this clever tacticClaim that the bug is just a test, and it's totally not a bug at all.
Read more about this dubious excuseBlame it on someone else, preferably the intern.
Find out how to pass the buckClaim that the bug is actually a "design choice" and you're just being innovative.
Learn more about this questionable artistic vision