I once wrote about the similarities between Malaysian (especially Malays) and Indonesian which are due to the same roots that both country have (the link can be found here - http://howmanthink.blogspot.com/2009/01/indonesia.html). This is true as much as most Malaysian wouldn't be caught dead being said to be an Indonesian. As most Indonesians who work in Malaysia are maids and hard labourers, Malaysian treat them as such. As Malaysia and Indonesia as a country itself had their own conflict which nearly escalate to full-blown war, thankfully averted, the people seems to do the same.
However, as much as we are the same, I sometimes wonder how history can lead us to be so culturally different. The language, the meaning od the same word and the reference to the same brand but different usage for it. Of course the similarities are there but as we chart our own course, we tend to divert from the same path. Malaysia took the road less familiar by transforming itself from a small country to a country vocal on it's stand (regardless of the people's stands) and Indonesia just trying to survive everyday life as it encompass nearly the whole of South East Asia.
Taste of food, how you order certain food, education, politics and culture. Malaysia and Indonesia once even fight over the song's origin as Malaysia used the song 'Rasa Sayang Eh...' to promote Malaysia in Indonesia. In all actuality, all music history teachers knows that a cord or a tone being changed can turn a melody from being Chinese to Malay to Indian. Like the band Queen once asked in one of it's last song "What are fighting for?".
It's not that bad if you look at it on certain point's but Indonesia is to Malaysia is like Malaysia is to Singapore. One is considered poorer in term of economic reach but the other always hated the other's for it. It is the perfect example of can't live with them, can't live without them. Truth be told, being neighbouring countries, we depend on each other.