In setting up Firewall rules, whats the specific reason that there are 
separate rule lists for LAN, WAN, OPT1 interfaces?  Afterall, aren't i 
defining the interface implied when I specify the SOURCE and DESTINATION 
interface in the rule itself?

It seems redundant, and, at times, conflicting:  What would be the purpose 
of say setting up a rule that allowed traffic between LAN and WAN but 
applying it to the tab under the OPT1 interface for example.

Am i missing something?