Everyone wants to be simple. Perhaps it has always been this way, or perhaps it's an effect of the cognitive crisis, but it's a rare thing to see a brand manual that doesn't have the word "simple" in it's list of brand values. But there are two distinct and opposite ways to simplify.
Abstractive simplicity is about finding a lowest common denominator. People LOVE doing this type of simplification. It's where you can take your entire list of brand values – three, seven, ten, I've seen as many as thirteen – draw a circle around them and sum them up with a lowest common denominator. This generates concepts and taglines along the lines of "Quality Together", "For Your Future and Beyond", or something containing "...Life" – because not a lot of things fall outside of "life", right? If you're not an coffin maker or a metal band I guess.
Reductive simplicity is about cutting away everything that is not absolutely necessary to achieve simplicity. People HATE doing this type of simplification because they have to make really tough decisions about which limbs to cut off from their brand body. This is really really painful to do, so people prefer not to. The latin meaning of the word decision is literally "to cut off from". No wonder people are indecisive.
Reductive simplicity always wins when it comes to communication because it requires very little decoding and is cognitively much cheaper.