1. Some people get a thrill/pleasure from every victory, so they turn many interactions into a competition to create more victories.
2. Some people want to prove they are better than one person, so they create conflicts to win - you know it is personal when the conflicts are only with you.
3. Some people constantly create conflict in an effort to drive you out of a group or workplace, if you're someone who hates conflict or drama.
4. Creating competition and winning it is sometimes done by someone to win little fights and try to use that as justification for higher status in the workplace. It is the aggressive version of the passive-aggressive resistance to undermine you or use of gossip as petty passive power.