1)    One may not add extra steps on to the three steps which one has to take at the end of the Amidah, as by doping this he is acting in a way which is considered arrogant, in that he is showing that he gives more honor to Hashem than other people do. (Mishne Berurah 123)

2)    At the end of the three steps the custom is to say “Yehi Ratzon Sheyibaneh Beis Hamikdash …” (May it be Your will that the temple be rebuilt…), as the prayer is really only standing in place of the service of the offerings in the temple, and we therefore request that the temple should be rebuilt speedily and we will be able to serve the service of the offerings themselves. (ibid)