I have a big heart for this one because the tunnel is pretty amazing. It makes for such a huge straight line instead of a massive detour around Mount Washington and then into downtown. It's easy, it's clean, it's FREE and it works very, very well.
Please pay attention as you're driving, watch the road and the cars in front of you and don't change lanes. While this tunnel is amazing at keeping the traffic moving, it really doesn't take much to completely F it up.
Love the view as you come out from the tunnel and onto the bridge. Wowza!