There is a difference between a weaker brother, who may sin against his conscience when he follows your example and a controlling brother that will teach you and try to control your behavior through bad teaching.
For instance, one may feel it a sin to watch TV. Upon seeing you, a man he admires, watch TV, he himself may watch it even though he thinks it a sin. Thus, in his heart, he now feels convicted because whatever is not of faith, is sin. He is a weaker brother that sinned against his conscience. Such a one, we should give up our freedoms for.
The other will go and preach to you that you should give up your TV even though there is no reason to do so. He will not follow in your example but rather, teach you to follow his. He will preach as he did in Galatians that such things are the laws of God even to the point of saying one must do it to be saved, in some cases. In so doing, he is a controlling brother.
The one gets mercy. But not the other.
So we behave differently for the weaker brother than we do the controlling brother.
"May the Lamb that was slain receive the just reward for His sufferings." A quote by Moravian missionary that sold himself (along with a friend) into slavery to reach those that the slave owner prevented from hearing the gospel.
May I live for Him and not for me.