I see error messages in Hazel's log and, whilst I am not aware of any failure of Hazel to work, I know that I may well not recognise it if Hazel doesn't do something! I looked at the log when trying to see if something I had uninstalled had provoked Hazel's appsweep to clear up and saw "Uninstall log entries appear to be corrupted" and "Error archiving uninstall log":
2015-06-07 01:00:01.410 HazelHelper[413] Uninstall log entries appear to be corrupted.
2015-06-07 01:00:01.410 HazelHelper[413] Error archiving uninstall log: Property list invalid for format (property lists cannot contain NULL)
2015-06-07 01:00:01.441 HazelHelper[413] Purging old trash database file: /Users/sarah/Library/Application Support/Hazel/trash-16777228-1787.hazeldb
2015-06-07 07:54:10.053 hazelworker[3716] ###main load address: 0x10a49b000
2015-06-07 07:54:10.105 hazelworker[3716] ###Noodle load address: 0x10a5ad000
2015-06-07 07:54:10.105 hazelworker[3716] ###CK load address: 0x10a575000
2015-06-07 07:54:10.567 hazelworker[3716] Processing folder Downloads
Is there something I can do to get rid of the error messages?