For some reason, sangria makes me vomit - and I mean, only 4oz of it. Found that out in college.
One time I had a class of punch at a fly-in lunch, and got ill almost immediately - I couldn't really tell what was in the punch, and rooted around in back in the garbage cans _ yup - sangria. No idea why.
You must start with a really GOOD Spanish red for proper sangria.
Wine does that to me now, use to hand zinfadel well...