I remember the first hefeweizen I had. It was made by Widmer, and I didn't like it. The second time I tried it, I noticed there were pouring instructions on the box/bottle.
The instructions said to pour two thirds of the beer in to a glass, swirl, then pour the remainder. They even have an official YouTube video on it. I gave it a try, and maybe it was my imagination, but it tasted surprisingly different. I liked it.
What does rolling/swirling a hefeweizen actually do?