Though you might get along really well for a time, you'll realize after a while that there's some sort of disconnect in your communication. At some level, your friend won't be entirely honest with you. This could be a major pattern of willful dishonesty, but it's more likely to be as minor and intangible as them holding a part of themselves back out of insecurity or because of past experiences -- and then you'll follow suit when you pick up on this strange vibe.
Confused communications will be the norm between you. The lesson of this aspect is to be yourself and communicate as honestly as you can, even when being honest makes you both uncomfortable.