I'll tell you why...because Allah (swt) says in the Qura'an...
"And verily, this is My Straight Path, so follow it, and follow not (other) paths, for they will separate you away from His Path. This He has ordained for you that you may become Al-Muttaqun (the pious)." [Al-Anaa'am 06:153]
Well let's think about it...
Allah's Straight Path (or *deen*)..is *already* completed..and decreed for all humanity to *follow*..and this is confirmed in the following verse...
"This day, I have perfected your religion for you, completed My Favour upon you, and have chosen for you Islam as your religion." [Al-Maae'eda 05:03]
And we follow Islam through the Shari'a containing The Qura'an and The Sunnah..so *taking away* or *adding* anything to it (i.e. Islam)...will cause a *distortion* in it..and that distortion would in turn create a *misguidance*..so the straight path or the deen..may *no longer* be Allah's Straight Path..or Allah's deen..it would be *the innovation* of mr. this or sister that...and Allah (swt) does not accept *anything* but *His Deen* and *His Path*...and this is apparent when He (swt) says in the Qura'an...
"The command (or the judgement) is for none but Allah. He has commanded that you worship none but Him; that is the (true) straight religion, but most men know not." [Yusuf 12:40]
And...
"O you who believe! Obey Allah and obey the Messenger, and those of you (Muslims) who are in authority. (And) if you differ in anything amongst yourselves, refer it to Allah and His Messenger, if you believe in Allah and in the Last Day." [An-Nisaa'a 4:59]
And about *bida'ah* or innovations..Rasulullah (saaws) has said *specifically*...
"The most evil affairs are their innovations; and every innovation is error." [Sahih Muslim 004/1885]
And..
[FONT=Verdana, Helvetica][FONT=Verdana, Helvetica]"Indeed, the most evil of matters (in the religion) are the newly invented ones, and every innovation (in the religion)is [FONT=Verdana, Helvetica]a bid`ah,[/FONT] and every bid`ah is misguidance, and every misguidance is in the Hellfire." [Al-Albani][/FONT][/FONT]
So you see sister...innovations are a danger...even if they are "seemingly good"...they are a danger because they can *corrupt* the deen of Allah..and make it something that it is not..and if allow innovations to take place..then we'd become a people no different from the Christians and Jews before us..who took the deen of Allah and turned it into something full of corruption and blasphemies (wal 'eyatho billah)...
To keep our deen safe..and to protect our iman...we have to stick to what is within Islam and its Shari'a in the most trivial of matters
If you wish to read more about the topic..I suggest the following link...
http://www.turntoislam.com/forum/showthread.php?t=41332
Inshallah it will be of benefit..may Allah bless you and guard you..Ameen!