You must have heard of Jimmy Savile. Everyone thought he was a wonderful man because he did such an enormous amount of good, raising money for charity, no doubt feeding many who were hungry, giving of his own time to look after the sick, etc, ostensibly loving his neighbour just as Jesus told us we should.
However, at the same time he was breaking God's Law by abusing children left, right and centre for years. Can you by any stretch of the imagination say that that man, who no one denies did an enormous amount of good, actually showed any real love of God or his neighbour? Do you think that the good he did excused his behaviour in disobeying the divine Law?
How many times do we come across, say at work, someone who we take to be a wonderful person, kind, loving, caring, etc only to hear later that he was living a double life, cheating on his wife, or beating her, abusing his family, stealing or lying? Would we continue to say that that man loved God or his neighbour?