Phantasy Star, PS4 in particular... for me it just did everything right in a genre oversaturated in tired old medieval tropes and settings... it shattered the concept that RPGs had to be wizards and warriors versus dungeons and dragons... later the MegaTen & Persona series did the exact same thing... but, for me it started with Phantasy Star III, i went back and played I & II, and bought IV as soon as it came out...
i went into this thread thinking my answer would be Chrono Trigger, as i have beaten it more than any other game... but, upon reflection, my love of RPGs really took off with Phantasy Star III...