In the Star Wars universe, the Jedi are the epitome of the natural world — in touch with all living things through the force. Droids, on the other hand, are an entirely artificial life form… And while Jedi may manipulate the physical aspect of their bodies, they will never be able to see into a droid’s thoughts, or manipulate its will. And this causes an almost unconscious distrust or dislike of droids within the Jedi.
Among the regular citizens of the galaxy, droids are typically seen more as tools to be used — again, relegating them to a secondary class hierarchy, one in which slaves (on planets which allow them) are seen to have more rights/respect by and large.
Thus, when Yoda doesn’t recognize R2-D2, it is more because what Yoda sees is “an astromech with a blue head,” much the same way in which one of us may not call a piece of Ikea furniture by its proper name (Kløotvär) and instead merely call it a “table”.
Similarly, Obi-Wan may not have ever actually purchased, and therefore considered himself to have “owned” droids, despite at various times having droids assigned to his care as part of his duties as a Jedi Knight or later as a General during the clone wars.
The sad truth is, no one recognizes the droids because “all droids look alike anyway.” Yep. You got it.
This answer originally appeared on Quora: