My simple observation on realtime human opponents, having played a few RTS games online is that the youths who play this game (and they are mainly young teenagers) are only interested in winning, and in the fastest time possible. Hence 'the rush'!
Almost every game I have played online has seen my opponent race through the techs to get the most powerful units and 'rush' me as soon as possible, most games being over in less than 20 minutes!
This is not the way I like to play, being brought up on CMBO CMBB And CMAK, but this is what you have to face these days if you want to play online.