One man's meat is another man's poison is a proverb which means that one person can find something tasteful but the mere sight of it can repel the other. It implies that likes, dislikes and preferences of each person can be different.
If I enjoy watching thrillers but my friend detests them, then it becomes the case of one man's meat being another man's poison.
What may seem like a good opportunity for one can appear to be a setback for the other. Two persons can react differently in the same circumstances or situations.
1. Sale of foreign cosmetics in Indian markets is being welcomed by its users but is being rated as unfair by the local companies. It seems that one man's meat is another man's poison.
2. I hate keeping late hours but my friend enjoys her job which requires her to do night shifts. One man's meat is another man's poison I suppose.
3. John loves to eat peanut crackers but his wife is extremely allergic to peanuts. It is true that one man's meat is another man's poison.