In my mind, we're basically the beneficiaries of two top shelf actors who were handed the opportunity of a lifetime and ran with it. In OB S1 TM had no idea if the show was going to work and she was basically thrown into scenes with someone (EB) she openly fangirled, so A+ effort (as she did throughout the season). And EB was acting in her first official gig for the English market and so she was all in. It's not often you get two gifted actors who are offered equally challenging career moments on screen. They were both probably thinking, "This is make or break for me." Plus...natural chemistry. Heart eyes off the charts.