Sunni Muslim suicide bombing atrocities of the last few days s

I wonder why only Sunni Muslims are eager to blow themselves up.  One never hears ( I have been unable to unearth even one incidence of a Shiite suicide bomber with a cursory search of the internet) of suicide bombers from the Shiite Muslim community.  I wonder why that is.  Someone somewhere must have a credible analysis on this strangeness.  No matter what the Sunni terrorists do to the Shiites, the Shiites will just not blow themselves up in revenge and neither are they eager to go meet their 72 virgins.  They fight back in other less barbaric ways.  A cursory search of the internet also refused to yield up any beheading done by a Shiite Muslim.  There must be proof  of  at least one incidence ... but where is it?
Conclusion I have come to unless proven otherwise:  Sunni Muslims are the ones committing gross atrocities by  suicide bombings and beheadings.

In Pakistan:
 ...Militants opened fire on a Shiite Muslim mosque where worshippers were gathering for Friday prayers, and then a suicide bomber detonated his explosives inside, killing 15 people in the latest attack aimed at the minority sect, police said.

In Iraq
Suicide Bombers Kill 37 at Shiite Mosque in Baghdad. Suicide bombers killed 37 people at a Shiite mosque in the Iraqi capital on Tuesday, in the third consecutive day of sectarian attacks this week.
At afternoon prayer time, the two attackers gunned down three guards at the mosque, in the Qahira neighborhood in northern Baghdad, and then blew themselves up, killing 34 worshipers and wounding at least 57 more, the police said. The mosque is a popular place of worship for students from a nearby Shiite Islamic university.

Suicide Bomb, Shootings Kill 9 Northern Iraq.  A suicide car bomb and other militant attacks killed nine people in northern Iraq on Saturday, officials said, the latest in a wave of violence that has killed nearly 2,000 Iraqis since the start of April.
The deadliest attack was in al-Athba village near the northern city of Mosul, when a suicide car bomber rammed his explosives-laden car into a police patrol, a police officer said. Three civilian bystanders and one policeman died while six other people were wounded, he added.
With violence spiking sharply in recent months to levels not seen since 2008, al-Qaida in Iraq and other militant groups have been gathering strength in the area of Mosul, some 360 kilometers (220 miles) northwest of Baghdad....