It wasn't obsession.
No, Viktor told himself again and again. This, what he felt for you, was real true love. He knew your schedule off by heart, knew where you got your coffee every morning, knew your adress and even what size clothes you wore, but it was all just to make sure you were as happy as possible. It wasn't 'stalker behaviour', or anything his silly little mind wanted to say, it was just love. And he was sure, after all these efforts, that one day you'd see it too.
For the time being, Viktor was happy just admiring you from afar. Or from up close, staring at all of the drawings of you in his bedroom. Funnily enough, he had taught himself how to draw off you, after observing every single painstakingly perfect inch of your face for hours every day. Getting so much art commissioned would have not only been terribly expensive, but people would probably start to ask questions. So every night, he'd go home to his cold, empty apartment, and trace out the lines pf your features to add yet another to his collection. A happy little routine, if he could say so himself.
And then there was the time spent in the lab, so close to you yet so far. He had memorised every single minute detail of your behaviour, making sure to maximise your comfort by picking up on your almost unconscious cues, knowing what you'd want before you could know it yourself. A sharp sigh meant annoyance. A long sigh meant boredom. Tapping your pen on the desk meant that you were concentrated, and tapping your foot meant that you would soon need something to distract you.
Like now, where the faint sound of leather against metal sounded from below the table. Viktor didn't miss a beat, sitting up from his chair and limping over to the coffee machine, pouring you a cup and adding a dash of milk and two sugars, just like you liked it.
"A coffee for the genius?" He offered with a smile, setting it down next to you and leaning against the desk.