It is not appropriate for the Muslim to enter the bathroom except for the purpose of relieving himself, and when he enters the bathroom he should refrain from eating and drinking until he comes out.

The rights that one Muslim has over another are man; some of which are individual obligations that are required of each person, and if he fails to do them he is sinning. Others rights are communal obligations; if some people do them, the burden of sin is waived for the rest. And some are encouraged but not obligatory, so the Muslim is not sinning if he does not do them.