is being loud an offence??

an hour before today, one cousin of mine called up at my landline number. we were talking and because she is very senior to me and workng as a junior scientist so generally she was discussing about her experiences with her colleagues. we were laughing on some issue and i didnt knew when i got that louder . simultaneously one uncle was inside my house for some work. he was cool and didnt said a word...just was busy doing. but my papa enetred the room and looked at me eye to eye showing that he is angry. he enterd the kitchen and moved his hand communicating "is this a way to laugh when somebody else is inside??" incidently our chat got over and i put the reciever down. i passed him without looking at him and without uttering a single word and same he did.
phewwwwww
now the problem is from that moment itself i am feeling uneasy. uneasy because i didnt uttered a word when i knew that i was not wrong. to laugh heartily is not an offence. this incident only showed that i am a hypocrite. and the fact is that seriously my heart beats got double the speed when i saw my fathers expressions.
......................
what a pity?....i could not even defend myself....