Why does Dorothy miss the scarecrow most of all?

In the Wizard of Oz during the tear jerking final scene in Oz Dorothy wishes her companions a fond and tearful farewell. She wishes The Lion and The Tin Man all the best saying she will miss them and then claims she will miss the Scarecrow "most of all". Is Dorothy just a bit socially inept or was there a reason why The Scarecrow holds a special place in her heart?