Rule #7: Trust compliments from enemies and criticism from friends.
Corollary: Regardless of the source, good advice is good advice.
Some things are hard to come by. People tend to spew compliments pretty easy as social lubricants. O'course, as soon as the chips are down, most of those same folks will vomit forth a lot of criticism. No judgments (okay, some judgments); people sit on a lot of toxic shit to make civilization work.
The result is that honest, compliments and objective criticism are hard to find. Now, friends can tell you all about your strengths and foes can monologue about your shortcomings. There's no rule against either one.
Once they each break type and start the real talk, it's worth listening though.
The corollary is perhaps truer, if less useful. If advice is good, it's by definition worth taking. Odds are pretty good that if you could recognize a good idea as such, you'd want to use it anyway. But humans are humans and a reminder that the source shouldn't stand in the way is worth posting.
 Always listen to your friends.