i think that aliens would find it weird that humans have favorite things (animals, colors, brands) that have no logical source. example:
human: can you hand me that screwdriver?
alien: *hands one over*
human: actually, can i have the pink one?
alien: yes, but why? surely the one with the pink pigment is no different from the others?
human: yeah but pink is my favorite color
alien: does this affect how able you are with the tool?
human: no, i just like that color best
alien: ????