We humans are a strange bunch. Being equipped with the miracle of verbal and written communication, we get a 'pass' on something the rest of the animal kingdom relies on for survival: Speaking and listening in actions, not words.
It's taken me a long time to realize how poorly my action-related communication syncs to my verbal communication. I grew up believing it was OK to say one thing, but to do another. Many of us do. It's easy to fabricate worlds where we say one thing but do something completely contrary, and as a society few people call us out on the disparity. I'm not sure why this is. The best reason I've come up with is that few of us are tuned into "listening to actions, not words" enough to notice it.
As I've slowly become aware of the disparity, the main reason I've often failed to achieve parity between my spoken commitments and my actions is that it's a really, really hard skill to master. It takes meaningful, consistent effort to 'say as you do, and do as you say'. Life is full of small opportunities to massage the effect of one's actions with a stream of words that cover up the true meaning of the underlying actions. Our spoken (and written -- but mainly spoken, since it's more extemporaneous) communication acts as a type of elbow grease that makes interactions between humans run more smoothly -- or so we think.
Examples are plentiful and commonplace: