It is quite a common question if men and women can be friends. I am not going to comment on this; as I have been unlucky to end up falling in love with my best male friends and having them all gone, I am more eager to contemplate on friendship between two women. There are quite contradictory points of view on this matter, and though these are mostly men who say such friendship is impossible, most women agree it is harder for females to keep friendly relations up.
You may have great times together when everything is fine – go out for a glass of wine after work, discuss all the latest fashion trends, go shopping or simply gossip, encourage and support each other through tough time, share advice and life experience and just feel comfortable together, but in case you have to compete for something, all this friendliness and sincerity are instantly gone. Women are not generally ready to give something up for the sake of friendship, especially if it comes to dating a distinguished man or being promoted at work. So if you and your female friend have occasionally fallen in love with the same man or aim to get the same prestigious job, you have to give up the competition or compete fairly, otherwise you may end up being foes for the rest of your lives. However, not all women (this very well relates to men just as well) are able to play the game by the rules, abiding first of all to their moral values and being ready to compromise, so their selfishness results in having a friendship ruined.