A wise priest colleague remarked to me once that it takes ten years for a convert to become an Anglican: that is, to be truly formed by the liturgy and ethos of the classical Book of Common Prayer and the English spiritual tradition. Having been on this journey myself for so long now I definitely agree with that. Anglican formation is a very long and slow process. It involves a complete reorientation of ones general thinking, theological method, and spirituality. It is so slow, in fact, that half the time one doesn't even know it is happening! Once one is formed in the tradition, though, he could hardly imagine being anything else, and such a strong and solid base has been established that the spiritual life beings to really blossom. By far the critical error people make is thinking they know something of Anglicanism after just a few services, or a few years of membership in an Anglican parish, but after brief time, in frustration, they leave. It takes so much longer than that to really explore and experience our tradition.
On a related note, I wonder if it is even possible for anyone to get a truly Anglican formation in the Episcopal Church anymore, since that body has abandoned on a local and institutional level the classical Anglican tradition and rule of life. Because of that, I tend (perhaps wrongly) to be very leery of people who come to us from TEC proudly boasting that they are "life long episcopalians". I wonder what, if anything, they have learned about English spirituality in TEC - even if it is "conservative" parish. Lord knows they know nothing about BCP in many cases, and they certainly have not read even popular Anglican writers like C.S. Lewis, much less the classical divines, such as Jewel, Taylor, Thorndike, etc.
Our formation process is slow, and I think sometimes people get impatient with it. But things that grow slowly grow strong. And I think having strongly formed Christians is much better than having great numbers of poorly formed souls, which is, sadly, what many other churches focus on these days.