Boisterous applause and loud laughter are ungentlemanly.
It is in bad taste to distract your companion's interest from the performance, even if you find it dull yourself.
No gentleman should leave a lady alone for a moment in a public place of amusement. He may subject her to annoyance, or he may find another lady in his seat when he returns, which would separate him from his companion until the close of the performance; for, although a gentleman when alone should offer his seat to a lady or old gentleman who cannot procure one, he is not expected to do so when escorting a lady. His place is then that of protector to his charge, and he must not relinquish it for a moment.
Secure a libretto, or programme, before taking your seat, that you may not be obliged to rise to get one.
At the opera, conversation during the performance is in the worst taste. The lowest tone will disturb the real lovers of music. Exclamations of "Lovely!" "Exquisite!" "How sweet!" and others, are all proofs of vulgarity.
If you promenade at a concert or between the acts at a theatre, you may bow to friends the first time you pass them only. A lady must not allow other gentlemen to join her, if she would not offend her escort, and no gentleman will stop a lady to speak to her. A conversation of a moment or two is all that is allowable in such meetings.
If seats are secured, it is best to arrive about five minutes before the commencement of a performance; but if a gentleman is escorting a lady to an entertainment where seats cannot be secured, he should call for her at an early hour, that she may get a good place.
In a picture-gallery, never stand conversing before the paintings in such a way as to interrupt the view of others. If you wish to converse, stand aside or take seats and do so.
A gentleman alone may join lady friends for a few moments between the acts at a theatre, or in the intermission at a concert, but only for a few moments, as their escort has a prior claim upon their attention.
It is an act of rudeness to join any party about to visit a place of amusement, or at one, unless urgently invited, and no one of taste will ever form a third. If two or three ladies are in the party and but one gentleman, another gentleman, if well acquainted, may offer his services as escort to one of the ladies, and if not allowed to share the expenses, should invite the party to partake of refreshments after the performance is over.