Jesus in human form, left His father in heaven, to be fully with us for a time. He walked the earth experiencing fully what we experience so that He could fully relate to our human experience. He wept so that He could relate to our tears. He lost loved ones so that he could relate to us when we loose loved ones. He experienced pain and torture, so that we could recognize that He has fully experienced every bad thing we might experience. He performed many miracles while human, so that people could testify to the power given to Him by His Father in heaven. Or, not.
These are some examples of contemporary teachings that slip out of the mouths of Christians today. They resemble some thoughts from the Kenosis heresy introduced by Gottfired Thomasius which taught that Jesus gave up some of his divine attributes while in human form. That he was not fully divine. This teaching assumes that Jesus can not be fully human and fully divine at the same time. It further assumes that there is somehow a "break" or separation of the Trinity during the years of Jesus on Earth.
It may also closely relate to Nestorianism in that it attempts to keep Jesus Human separate from Jesus Divine. As Felker Jones puts it, "denies the mercies of the God who is powerful enough to have no need of our protection and loving enought to cry, suffer, and die for our sake." It comes from a place unable to conceive that complete divinity and complete humanity can exist at the same time in one form. Felker Jones points out that the incarnation does not work in two separate forms, "The one person Jesus is the one who commands the heavens and who weeps when his friend dies." There is no "while He was Human".