My family vacations growing up were often to National Parks, and Glacier is definitely my favorite.
On my first trip there, when I was hiking with my family on the Iceberg Lake trail, a couple appeared running back towards us with their bear spray pointed behind them. We were at first concerned that they were running from a bear, but a few moments later, a moose appeared behind them trotting down the trail. We turned around and booked it back down the trail until we found a spot where we could get off the trail behind some trees, and the moose ended up turning off.
That was quite a scare at the time, and it could have ended very poorly, but it makes for a great story now.