In my stories Bruce Wayne, 23, took in 8 year old Dick Grayson as his ward after his parents died. Dick was officially adopted by Bruce on his 14th birthday, even though he had regarded Bruce as his father for some years now. This was the best birthday present he could have wished for.
Dick doesn't mind using the last name Wayne at all even though he much prefers to go with Grayson-Wayne. That day was quite emotional but beautiful for both Bruce and Dick and they spent the whole day together for father and son moment (finally made official).
On his 18th birthday Bruce gave him a gift that rivaled his adoption (and that alone indicated how important and meaningful this gift was).
The gift was a true Wayne family heirloom: a watch passed down through generations and generations. Unfortunately, Thomas Wayne never had the opportunity to pass the watch on to his son, and the task fell to Alfred Pennyworth when Bruce returned from his world travels to become Batman.
Dick was, to say the least, shocked and speechless at the importance of the object Bruce was giving him, and tears began to accumulate around his eyes. Just as Bruce visibly panicked seeing the tears streaming down his firstborn's angelic face, Dick gave him a bone-crushing hug that they would both remember forever.
Dick loved his father so much, even though he could be a real emotionally constipated asshole at times.