The following is a summary translation taken from Sahab.net
http://sahab.net/forums/showthread.php?t=343068
بسم الله الرحمن الرحيم
الحمد لله
Benefit?smiling and laughing
The Noble Sheik Abu Abdullah Abdur Rahman ibn Sa?dee (ابن سعدي), may ALLAH have mercy upon him, said ?Therefore Sulaiman peace and blessings are upon him, heard her (the ant?s) statement and he understood it, ?So he (Sulaiman) smiled, amused at her speech? (Chapter 27 verse 19)
So he admired her advice to her nation and the good way she expressed herself. And this is the condition of the Prophets, may ALLAH?S peace and blessings be upon them, they had complete manners and they would show admiration or be impressed at the right times although their laughter would not go beyond a smile. Such was the Messenger of ALLAH peace and blessings are upon him, most of his laughter was (only) smiling.
Because verily boisterous laughing (القهقهة) is a sign of foolishness and bad manners and not smiling and being impressed at those things that are impressive is a sign of vile character and arrogance; and the Messengers are free from such a thing.
End of Sheik?s speech
Source: Tafseer ibn Sa?di (499/3)
وَكَانَ الْفُضَيْل بْن عِيَاض يَقُول : يَا كَذَّاب يَا مُفْتَرٍ , اِتَّقِ اللَّهَ وَلَا تَسُبَّ الشَّيْطَان فِي الْعَلَانِيَة وَأَنْتَ صَدِيقُهُ فِي السِّرّ
Narrated by 'Aisha (radiallaahu 'anha) : The Messenger (salallaahu 'alaihi wa sallam) said,
[Bukhari, in The Book of The Eclipse Prayer]
quote:
"If you knew that which I know, you would laugh little and weep much."
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Shaikh al-'Uthaimeen (rahimahullaah) once said:
quote:
If a blind man was to walk in a masjid these days, he would not know if he was in a masjid or suq (marketplace).
Wallaahu musta'aan.
Subhanak Allaahuma wa bihamdika ash-hadu anlaa illaaha illa anta astaghfiruka wa atubu ilayk
If I said anything correct, then it is from Allaah (subhanahu wa taa'ala), and if I erred, then that is from me and shaytan.