Both in terms of how much you sing:

A 35-year-old man was killed in a karaoke bar in Manila, the Philippine capital, after he refused to stop singing, police said today.
They said Danilo Celicious died instantly from multiple gunshot wounds in the bar in the suburb of Quezon yesterday.
"The victim and his friends were drinking and singing inside the bar when another group of men drinking at a nearby table asked that they stop singing," police said. "But the victim refused and just continued singing."
The suspects then attacked the victim and his friends and a brawl ensued.

And who and what you sing about:

A famous Iraqi singer who used to glorify deposed president Saddam Hussein was assassinated by armed men in his Baghdad home, neighbours said yesterday.
"I saw three people driving in a pickup truck around the neighbourhood on Saturday. One of them later came to the gate of the garden where Daoud Al Qaissi was standing and started talking to him," Samir Doush said.
"He was joined by an accomplice who fired at Al Qaissi's head. The bullet pierced through the glass of the house," he said, adding that the three then sped away.
Al Qaissi, who was in his fifties, headed the union of Iraqi artists, and had mobilised singers, poets, actors and painters during the US-led war on Iraq to sing the praises of the Baath regime and the army.
After the war, "we advised him to leave the house, but he refused, saying he would die some day anyway, whether here or somewhere else," Doush said.