Laying eyes on an incredably hot girl, who is just a little bit too young for you, and expressing your sexual interest with a "Sweet Jesus!!"
Sitting outside the pub and a group of scantily clad 17 year old girls walk past. Someone pipes up "SWEET JESUS!..." and everyone looks round to have a gander.
The "Holy Shit!" reaction you get when you scare the crap out of someone (or your pet cat).
Sweet Jesus! Where in the hell did that come from!