A rhetorical question: How did a word that (to my mind) means that a person is blessed by your gift (of time, attention, love, etc.) come to mean that you're crazy? Because that's what some people think when you give them a gift. Sad but true. "Touched" in the head.
"Wherefore doth living man complain, a man for the punishment of his sins?" (Lamentations 3:39, emphasis mine) "Life" being the essential and default—let alone greatest—gift.
Starting from the bottom up, we all have the gift of life. Yes, we have our ideas and ideals, ways of thinking and opinions about how things should be, but how many of us base our expectations in gratitude for what we already possess? And where does this attitude come from of constantly wanting more of what we want? And right now! There are times where I pray and expect something from God, only to receive an answer in some other realm of life. And I get all bent out of shape. I question motives, I become bitter and disbelieving and all the complexes that I thought had been laid to rest come bubbling up to the surface! Yay! Now they can be dealt with! Because anytime you'd think someone crazy for wanting to bless you, it really means you have issues with God.
Because He's where all blessing comes from. Gifts, all.
"Then touched He their eyes, saying, According unto your faith be it unto you. And their eyes were opened; and Jesus straitly charged them, saying, See that no man know it." (Matthew 9:29-30) This command of Jesus has always made me wonder. Why would he tell them not to share the miracle? Many reasons, I'd surmise. Firstly, when God gives you something—when He touches you—it's meant for you, first. The analogy of "casting ones pearls before swine" comes to mind. Secondly, we all have this blind spot where we think that other people feel and think the way we do. Oh, we'd readily admit that on the surface, they think differently. But I'm referring to deep undercurrents of thought/feeling/emotion/worldview (essentially weltanschauung—same thing) that are radically different, if not diametrically opposed to yours. Granted, there are only so many ingredients in the box and we—with whatever fraction of our gray matter we actually use—only deal with the tips of other people's icebergs, but realize: strangers can be so radically different from you that it's scary. Why not tell someone that you just received your sight? Because they're blind, too. Sometimes we should just keep things to ourselves. But there are other times where we run the risk of being seen as evil for doing the very thing that God said was the good. It's a matter of motive. From here to there.
"Let not then your good be evil spoken of: For the Kingdom of God is not meat and drink; but righterousness, and peace, and joy in the Holy Ghost. (Romans 14:16)
And this is where Christianity is radically different from every other worldview: Christians (theoretically, because of Jesus) are willing to give up their last breath as a gift to someone in need—should the Holy Spirit move on them to do so. A spirit of selflessness unlike any other. Granted, most life situations don't and won't turn out that way or that starkly but some people will most definitely think you crazy for being willing to give up your life (time, money, food, attention) to better theirs. When someone is dehydrated after, say, an extended trek through the desert, they'll need more than water to restore their health. If they've been dehydrated beyond a certain point, they'll need alkali salts or some other source of electrolytes. Otherwise they'll just throw up what water they do take in. It's like the inverse of drinking salt-water. Neither way are they going to be satisfied.
In closing, I would like to make honorable mention of Nebuchadnezzar. Oh, God touched him all right—brought him down a peg. In Daniel, chapter 4, he undergoes a transformation from proud, splendiferous, magisterial ruler—to certifiably insane. He came back to his senses when he glorified God for who He was and is (verse 37): "Now I Nebuchadnezzar praise and extol and honour the King of Heaven, all whose works are truth, and His ways judgment: and those that walk in pride He is able to abase."
Maybe that's how the other, negative connotation arose?