It's entirely possible for such things to happen in real life. In fact, I'd say the alternative is more unlikely to happen than being in the Friendzone... well, at least in my country anyway. Not sure about America.
That said, it's rather unrealistic to go into a VN with the expectation of Friendzones, because Friendzones are unrealistic in VNs. There's always a harem or two waiting around the corner of your next VN.
I mean, seriously, have these writers never heard of a little dialogue called, "I just don't feel that way about you, baka shounen protagonist."