Why do guys make it so difficult?

Why does a guy make things so difficult for a girl who likes him, why give her so much pain and hurt if he never was interested? He first conveys the impression he likes her, is attentive and caring, texts and calls her on the days they cannot meet, presents possible solutions to potential problems put up by the girl, and when he has near about convinced the girl that he may just possibly be the one, tells her he cannot reciprocate her feelings?? Do they derive some sadistic pleasure from toying around with a girl's sincere feelings? Have any guys ever felt the same about a girl?