> There was an interesting psychological study recently that showed the best gift (in terms of how happy the receiver is) reflects the personality of the giver rather than the recipient

That's great, but you claimed that your partner wouldn't like it if you try to predict what they would like. The link you provided actually says the opposite: that people say they prefer gifts tailored to their preferences, which means they wouldn't mind you predicting what they'd like, contrary to your original claim.