I am buying a box of tampons.
Deduction: I am a woman and I get my period, and am low on tampons regardless of whether I have my period now.
Assumption: I have my period now.
Interesting assumption: I have my period now, so I must be in a [female dog]-y mood.My husband is buying a box of tampons.
Deduction: a female in his life has asked him to pick up tampons.
Assumption: his wife made him add tampons to the list.
Interesting assumption: he's really a transvestite woman and is on the rag.