This guy went into the bar Friday night and ordered three beers, in fact every
Friday night he went into the bar and ordered three beers and drank them all by
himself. Three beers...every Friday night. Not 2. Never 4. Always 3.
Well, the bartender couldn't  figure this out. Without fail this guy
came in.
The bartender finally said to the guy, "Every Friday night you come in
here and have three beers. There must be a story to this. You never order 2
beers, or 4 beers, always 3."
The guy said, "Yes there is a story. You see, me and my two buddies
always went out for a beer on Friday night when we were in Vietnam.
One night while we were drinking we decided that we could continue doing this
when we returned to the States. We also decided if one of us didn't make it the
other two would drink the third one's beer. And if two didn't make it, the third
guy would drink the other two beers. The other two didn't make it back so I'm
drinking theirs." The bartender felt bad.
Well, the next Friday night the guy came back into the bar as usual but only
ordered two beers. The bartender couldn't believe it.  Friday after Friday this
guy now ordered only two drinks. This went on for some time and the bartender was
so puzzled he just had to ask the guy about it.
The bartender said to him, "I notice you have only been ordering two
beers for the last few weeks. There has to be a story here."
The guy said, "Yes indeed there is a story. You see I joined the Mormon
church and I can't drink beer any more."