Here are just a few examples in support of my case that God has done horrible things (all excerpts taken from the NIV):
Sending Bears to Murder Children (2 Kings 2:23-24)
From there Elisha went up to Bethel. As he was walking along the road, some boys came out of the town and jeered at him. "Get out of here, baldy!" they said. "Get out of here, baldy!". He turned around, looked at them and called down a curse on them in the name of the Lord. Then two bears came out of the woods and mauled forty-two of the boys.
Why would God maul 42 children just because they were teasing a man for being bald??? There's a serious disparity between punishment and crime there. God murdering 42 children for this is a horrible thing.
God Killed SOOO Many People (Too Many Passages to Cite)
If you add up all the people God has killed in the Bible - not even counting the mass death that isn't even enumerated in the Bible like Noah's flood and the first born of Egypt - do you know what number you get? Approximately 2.5 million people! If you estimate the number of people killed in the events that aren't enumerated (the flood, first borns in Egypt, Sodom & Gomorrah, etc.), the estimate is about 25,000,000 people. Killing 2.5 million people - let alone 25 million! - is a horrible thing.
Helped Samson Kill 30 People for Their Clothes (Judges 14:1-19)
Then the Spirit of the Lord came powerfully upon him. He went down to Ashkelon, struck down thirty of their men, stripped them of everything and gave their clothes to those who had explained the riddle. Burning with anger, he returned to his father’s home.
Couldn't God have just given Samson the "thirty linen garments and thirty sets of clothes" that he wagered on this riddle? Sure, maybe Samson's wife helped the betters cheat by crying for a week until Samson told her the answer to the riddle. But to help Samson kill 30 of his wife's people as punishment...that is a horrible thing.
Killing Israelites who Complained About God Killing Israelites (Numbers 16: 1-49)
The next day the whole Israelite community grumbled against Moses and Aaron. “You have killed the Lord’s people,” they said. But when the assembly gathered in opposition to Moses and Aaron and turned toward the tent of meeting, suddenly the cloud covered it and the glory of the Lord appeared... Wrath has come out from the Lord; the plague has started... He stood between the living and the dead, and the plague stopped. But 14,700 people died from the plague, in addition to those who had died because of Korah.
Sure, the Israelites were complaining a lot for people who had just been rescued out of Egypt, but - again, in sending down a punishment far in excess of the crime - God killed 250 people. And then when more Israelites started complaining about the fact that God just killed 250 people, God kills another 14,700 people! That is a horrible thing.
Poor, Poor Job (Job 1)
I'm not even going to provide direct quotes for this one because, well...it's the whole chapter. But to settle a bet with Satan, God let's Satan ruin Job's life. He destroyed his farm, his livestock, his servants...and, oh yeah, his entire family. Job was an innocent bystander who loved God. And yet, God destroyed his life to settle a bet with Satan. That's a horrible thing.