It never really changed my life but the I fell in love with it. At the time it was darker than most Zelda game's, and the feeling of dread knowing you have a time limit to save the world. And the idea of being able to turn back time and able to save people again was just a cool idea to me!
Dance Dance Revolution. Starting in middle School I got really lazy and started putting on weight, in part because I lived practically in the middle of nowhere for 3 years. Saw some guy going crazy on a machine at Six Flags and was immediately interested. Ended up going from chubby to underweight... Because I had gone a little too crazy and had this stupid fear of eating... Well now I balance my diet and exercise better. Pretty much DDR eventually set me on the path to a more healthy life style (after the anorexic phase), so I guess it's what changed my life the most.
Tales of Vesperia and Fate/Extra CCC
Runescape, Ah golden days ^-^
Rather than make a gigantic list of games, half of which nobody has ever heard of, I'm just going to go with Persona 5 because that's what I've been playing.
Shining Force 2 was the game which introduced me to the fantasy universe of RPGs. It's the Mega Drive gem. And the post-ending scene when the witch from the main menu returns to her original form is one of the best endings a game could have.
Either metal gear solid: snake eater, or mass effect 1 or batman:Arkham asylum.
Star ocean series
Every tekken, soon to be seven aswell. I have literally grown up with this game franchise and it means a lot to me.