What is the proper behavior in the shul in regard to parents and children?  The Mishna Brura 98:3, cites the Shaloh HaKadosh who strongly criticized parents for bringing children to the shul at an age where they cannot be educated and controlled not to run around and disturb the congregation.  

Not only does this affect the decorum and intensity of worship, but it affects the entire attitude and behavior of the children as they grow up to develop an attitude of disrespect and almost contempt for the sanctity of the synagogue. Only when children have reached some age of being able to behave in a proper manner during davening should they be brought to shul.

In that same section of the Shulchan Aruch, R’ma rules that “it is forbidden for a person to kiss his small children in the synagogue in order to establish that there is no love as great as love of Hashem” (Cited from Sheilos UTesheuvos Benyamin Zev from Sefer Agudah).  

Harav Kook, O.B.M. ruled that this does not only apply to parents and little children but any outward display of physical affection for friends or relatives etc. (Orach Mishpat, Orach Chaim No. 22).  

Rav Ovadiah Yosef also cites these sources and is emphatic in stating that is it prohibited for anyone to show this display of love in the shul.  However he writes that in promulgating this ruling it should be done in a most relaxed and non-contentious manner. 

The custom of the Sfardim of kissing the hand of parents or of the Rav is proper because as he explains it is a sign of reverence and respect which does not impinge on the boundaries of love relegated to Hashem. (Yichava Daat, IV, 12).