While incredibly friendly, management is also incredibly strict - they have to be when peoples' lives are in your hands while zipping them 200 feet above the ground. You can have fun, but you have to get the safety down perfectly every time. It's not as hard as it sounds!
As mentioned above, job is inherently risky. You're properly connecting people (and yourself) to lines and zipping them many, many times a day. You cannot make a single mistake ever.
Hours can sometimes drag if it's a particularly hot day or if you get guests who are terrified.
Tours tend to take two hours, and since they're only separated by short time gaps, there is a LOT of pressure to keep things paced perfectly - not so fast as to catch up with the tour ahead and not too slow as to force groups behind to wait for you. This is harder than it sounds when muscle memory is only part of the job. Keeping guests corralled, engaged, and safe absolutely affects the pacing, especially if they're scared.