You know when someone gets hired to work with you and they are just perfect and they are smart and they never bitch about work, and they "get" everything and the are totally independent and capable and fun to sit next to? And the co-worker is similarly appalled by the global phenomenon of inappropriate apostrophes? And brings in new music for you to listen to?
Well you know when they leave to take a different position in the company and she, I mean, that person or indeterminate gender, abandons you for the music station and leaves her position to be filled by someone who could probably never be as competent and fun and cool?
Could anything at work bum you out more? Answer: no.