My first big event was Rhino 2, I believe they were locking the gates there if I'm correct. Thought to myself, "wow this is cool shit"
I started 5 years ago, made the switch from paintball/woods ball because I enjoyed more tactical based games.
For myself personally Milsim, means being organized into military style units with leaders, command, a set structure and clear objectives. It's not about size, but quality of game play.
I don't expect to be in a gun fight all the time, but for me I'd expect 3-4 good battles in a 24hr period. Setting up a FOB, ambush, going on patrol, providing support and relieving other squads, taking prisoners, gathering Intel, it all speaks to me.
Yes I want to sling plastic, but I also want some strategy and realism. I don't want to guard a position for 8 hrs that will never see contact. If digging a hole is required for me to fortify my position, then I dig. I don't want senseless random tasks because that's what they do in the real military.