The Orthodox have a much relaxed way of doing Communion. You can come whenever you want, and leave whenever (which is why they last longer than Catholic ones: they're relaxed).
This doesn't please Catholics (in my experience) and anyone who's used to more solemn rituals.
As to Swedish preachers (didn't know that existed still), they're most likely Protestants, and so the waifers are just chips to them.
The best explanation I got for transsubstantiation was that of Father Robert Barren (on YouTube), but the explanation is that the word changes the world, even if you can't tell by any empirical means. In that sense, it is the body of Christ, although it's just bread. This is based on the idea that God created the universe by ideas, mind, and thus this world can be changed by ideas too, or something of that sort.
I've eaten the Eucharist once in my life, out of genuine faith (and have been reproached for it ever since) but I can't say I felt any different from having eaten a chip.