Plat already knows I am a FORMER hacker so I will take the time to explain this to you right now .
A filter is like a 3rd party program , you need to use something to inject it (Ie; WPE,Fiddler ,ETC)
filters affect the game ,with filters you can do anything from anti kick to entering locked doors.
Using filters is against zynga's terms of service which you can find here>
WONT LET ME POST LINK::
but most people don't give a rats ass about that policy.
FYI : There is a difference between packet editing and using filters.
Packet editing is basically changing a current items id into a different item (with its id ).
Ie; Changing ultra black spiky to white gold ninja hair , that would be packet editing.
Packet editing ONLY works for HxD , while with HxD (Packet editing) you can use anti kick for example, you can also do that on WPE.
I hope I explained this well enough for you.