All relationships at work (& home) are based on bed-rock of equality &mutual respect. Occassional mis-indulgence could get ignored but as a permanent feature with negative agenda, it is pure disaster. One-up-manship at times is a subconsciously learnt behavior which w'out realisation shows-up its ugly face. The other person may remain initially silent but rot sets in. Reciprocity follows. 1. Be conscious.You could be the one with the one-up-manship behaviour problem. Take feedback. 2. If it's the other, get into sincere conversations. Recall incidences. 4. Identify sensitive zones with a plan to avoid it. 5. Intentionally never do it. Apology helps.