Mac Mail Rules are acting on some of my friendly emails

Mac OSX v 10.6.8

Mac Mail v 4.6 (1085)

Has anybody got any ideas about this one please.

I've set up a long list of Mac Mail rules to try to divert spam mail into a separate folder.

However I've done something wrong somewhere because some of my friendly mail is also being sent into this folder.

Is it possible to find out which rule is the offending rule the next time this happens ?

Thank you.