Check here: http://mountandblade.wikia.com/wiki/Vassals
Barring quarrels, Rule of thumb is:
If they have no fife, and you are giving a fife to a lord with a fife, all lords will get pissed.
If they have a fife, and you are giving it to a family member, most lords will be happy.
Honorable lords and good natured are happy if you give it to Honorable, good natured or martial lord
Calculating lords stick together
Dishonorable lords hates everyone except their family
So basically, pick either all super dishonorable lords or pick all honorable/good natured/martial lords. The latter is always better unless you want to RP, since they answer to calls more and tend not to quarrel as much.