oh!! i just noticed that the instagram photos yuuri sees at the beginning of the anime outline his day before the finals!
first pic is victor, which, i just assume is showing that hes spending the day w/ victor.
after that he sees a picture of phichit sightseeing, which maybe inspires him to ask victor to go sightseeing with him?
then he sees jj sharing the engagement rings he and his fiance have. this most likely plants the seed in yuuris mind to get his own set of rings for himself and victor
finally he sees the picture of yurio, which is how he ends up ending his night before the finals.
since yuuri showed some anxiety about his previous performances after seeing these pictures, i was thinking that maybe the reason he was acting so “out of character” and asking to go sightseeing and shopping with victor was because after he saw the pics he wanted to try something different from how he normally isolated himself from other skaters/activities before the competition?