Working in an office environment will often provide tense relationships. The worst one that can occur is when you don’t like someone that you manage. While you can avoid someone in another department, ignore that boss you hate, and anyone else in the office when you dislike the person that you manage it can spell trouble.
The first thing to try and address is why you don’t like the person. If it is based on their performance, then great, call them out and if they don’t fix it, get rid. If it is based on an annoying personality trait like a strange laugh, then you need to grow up a little. If it is based on their personality and you both just clash, then little can be done but you can’t hold it against them. Remain professional.
The key is to ensure you don’t let that interrupt their performance reviews. Remain totally impartial. If that employee ever does do something wrong and you both know that you don’t have a good relationship then it is a good idea to include someone else in the dialogue or make them aware of the situation. If the problems with their work escalate and they can show a history of malice between you both, you will be in a lot of trouble. Remain professional.
Don’t feel the need to give them special treatment to counteract the personality clash. It is ok not to like them and you don’t need to pretend. When making big decisions like who to get a promotion, try and get a perspective from your peers in the office to ensure bias is not impacting your decision. Remain professional.
Finally, if all else fails, just distance yourself a little. While you need to do monthly or quarterly reviews you don’t need to micromanage them. Leave them to work on their job and you do yours. Interact where you have to and most importantly, one more time, remain professional.