When you work for some time with MOSS 2007, sometimes you might overlook some inconsistencies within the product.  Here is a quick list of quirks(now say that fast!) with MOSS 2007

1. When you have a Gantt view of the Task List, Web part connections are unavailable.  Hence you cant filter a Gantt View using the Filter Web Parts
2. DateTime columns cannot be used for Grouping in the Content Query Web Part out of the box
3. You cannot use the PortalSiteMapProvider to retrieve Navigation items from another site collection
4. If you have a Date Column in a List, it cannot be used as a Lookup Column on another List
5. When you use the Content Migration APIs to transfer content from one farm to another, people fields do not migrate accurately