I wanted to use my watch as my shopping list. So I created a google calendar item on my computer with the subject being the items I wanted to collect in the store. It all seemed to go well. In the store I opened the notification and left it open. First look at the watch "saw the first 3 items and picked them up". A couple of minutes later I looked again (using "look at watch" gesture to wake the watch up) and looked at the next few items. All good so far. So now it's time to "look at watch" to look at the last few items on the list and the notification has gone. Scrolled the dial wheel left and right and it was nowhere to be found. Looked at my calendar on the watch and could see all my meetings upcoming later in the day but not my shopping list event. Gone !!
From the time I brought up the notification first in the store, I never touched my watch a single time, relying on the look at watch gesture to re-look. I couldn't have dismissed it.