I gave my T a card, which was in his favorite colors. The inside read, "What can I say to someone who has done so much for me, who means so much to me, and who holds such a special place in my heart? All I can think of is, thank you, thank you, and thank you again." Since it was the last time I saw him (he had to quit his practice due to sudden and severe illness), I signed it, "Much love and many prayers."
I had given him small Christmas gifts over the years, such as crocheted, beaded snowflakes that he hung in a window in his office. Sometimes I gave him chocolate, because I knew he really liked it.
He always said something along the lines of it was very much appreciated, but completely unnecessary. I told him I knew that, and that if it were necessary for me to give him gifts, he'd never get any from me.