Some climbers use the term “peak bagger” pejoratively, implying the climber in question is more interested in crossing off mountains on a list than climbing for the sheer joy of it. Teresa Gergen is an unusually prolific peak bagger — and she’s proud of it. “I thoroughly enjoy rock climbing and the mountaineering that I’ve done, but I’ve been a list person since I was a young child,” said Gergen, a Denver climber who recently became the first person to climb all 846 peaks over 13,000 feet in the 48 contiguous states plus Hawaii.