Firstly, reflect on whether it’s the way you are giving instructions. Sometimes, we tend to speak too harshly without realising it. If so, you can try to change your tone of speaking. An extra “please” or “thank you” can make that difference. It might also be in your body language. Are you turning away even before your colleague finishes his sentence? Or not looking at him when he’s trying to discuss something? These can also be rectified.

On the other hand, it might be your colleague might be taking it too personally. It could be an age thing, an ego thing, or even plain jealousy. Unfortunately, this is a sticky situation that can’t be resolved by you alone.