I tend to feel a bit stressed, only because I try very hard to do it right, and usually have other things that ought to be doing instead. Plus, I usually find I haven't planned and prepared as well as I should have.
Once I get the techniques down, and more familiar with the equipment, I would probably relax more. Having friends over helps. Someday I hope to get my friends up to the point where we can brew together as "equals". My usual buddy enjoys hanging out and helping, but he doesn't read up on it and he's usually just doing this or that if I ask him to, but mostly just BSing.