D&C 88

As the Savior returned to the topic of holding solemn assemblies, He provided instruction on how such should be held and in what manner to participants should prepare.  I will note in my mind, modern day priesthood meetings and priesthood leadership meetings follow much the same instruction.  In holding such meetings, the Lord instructs -

"...the order of the house prepared for the presidency of the school of the prophets, established for their instruction in all things that are expedient for them, even for all the officers of the church, or in other words, those who are called to the ministry in the church, beginning at the high priests, even down to the deacons—
128  And this shall be the order of the house of the presidency of the school: He that is appointed to be president, or teacher, shall be found standing in his place, in the house which shall be prepared for him.
129 Therefore, he shall be first in the house of God, in a place that the congregation in the house may hear his words carefully and distinctly, not with loud speech.
130 And when he cometh into the house of God, for he should be first in the house—behold, this is beautiful, that he may be an example—"  (Doctrine and Covenants | Section 88:127 - 130)

I have always argued that when a priesthood leaders calls a meeting, he should be there early to see all things are in order where the attendees feel welcome.  No attendee should come to a meeting not having a presiding or responsible leader present. 

These meetings should be conducted as guided by the Spirit where the presiding authority should speak, and not only speak, but be allowed to give concluding remarks if guided by the Spirit.  After a presiding authority is given the opportunity to provide concluding remarks, the meeting should adjourn.

These meeting should be conducted where -

"...as all have not faith, seek ye diligently and teach one another words of wisdom; yea, seek ye out of the best books words of wisdom; seek learning, even by study and also by faith."  (Doctrine and Covenants | Section 88:118)

"Even by study and also by faith" does not follow the methods and philosophies of men.  Faith must be included.  All are to prepare for such meetings as follows -

"Organize yourselves; prepare every needful thing; and establish a house, even a house of prayer, a house of fasting, a house of faith, a house of learning, a house of glory, a house of order, a house of God;
120 That your incomings may be in the name of the Lord; that your outgoings may be in the name of the Lord; that all your salutations may be in the name of the Lord, with uplifted hands unto the Most High.
121 Therefore, cease from all your light speeches, from all laughter, from all your lustful desires, from all your pride and light-mindedness, and from all your wicked doings.
122 Appoint among yourselves a teacher, and let not all be spokesmen at once; but let one speak at a time and let all listen unto his sayings, that when all have spoken that all may be edified of all, and that every man may have an equal privilege.
123 See that ye love one another; cease to be covetous; learn to impart one to another as the gospel requires.
124 Cease to be idle; cease to be unclean; cease to find fault one with another; cease to sleep longer than is needful; retire to thy bed early, that ye may not be weary; arise early, that your bodies and your minds may be invigorated.
125 And above all things, clothe yourselves with the bond of charity, as with a mantle, which is the bond of perfectness and peace.
126 Pray always, that ye may not faint..."  (Doctrine and Covenants | Section 88:119 - 126)

In that this revelation is in regards to "solemn assemblies", there is a time and place, and "type" for laughter and humor.  This is different from "loud laughter" which I perceive as rudeness and light-mindedness.  We are always to be happy and cheerful.  That we "not faint" suggests that our faith does not fail.