Well according to the creator of Dilbert, Scott Adam's, there's a simple rule to remember about friends and whether they're being disingenuous about your ideas (although in his context he's talking about writing a comic strip).
Don't listen to your friends who tell you your comics are hilarious. They're lying. Don't listen to your friends who tell you your comics suck. They're idiots. The only reliable feedback is the copy test, i.e. does someone want to copy your comic and show it to someone else who you don't know. If someone says he likes your comic but he doesn't ask to copy it for someone else, he doesn't really like your comic.