Playing a robot is possibly the most difficult role you can have as an actor, because you have to take all your innate emotional responses and completely suppress them. Even the way you walk is affected. ↗
It's all about creating a back story for the character and developing emotional responses that are true to life in relation to the character. It isn't necessary to live a tragic life to create from that place. ↗
There were time when I was into method acting that I did have moments of residual character emotions, because the method bases your emotional responses as a character on emotional experiences from your real life. ↗