Has to be the diversity of operations in the industry for me.
Best pictures I have are from the Beautiful Scenery of the Alaskan Range and Brookes Range while pushing 500s and 350s to the max moving stackable core drills.
Most challenging flying has been in the short haul Powerline construction and Aerial Saw sector.
Most frustrating has been moving seismic recording equipment in the triple canopy Appalachians with the BagRunner.
Best comradery had to be working with Bristow in the old days. Most boring flying was also hands down the offshore sector.