I would establish a no physical abuse boundary with my siblings. The other 3 answers are known to be detrimental in having a relationship with someone. Conversation and laughter are ways to know someone better and relate to them in a positive way. All in all, complaints are useful as they can identify something wrong done by a person and may be very helpful for the person to correct their mistake. Physical abuse simply provides harm which leads to a negative relationship. Siblings are some of the most important family members in your life, so keeping a good relationship is necessary. Hope this helped :))