I understand that we all pay for the gym, and that everyone has a shot at the equipment.
That said, first come, first served. I have waited patiently and even modified my training days/times to coincide with optimal equipment availability.
If I'm squatting, plan to wait on me. Why? Maybe because I'm a dick, as I'm sure some will see it. From my end-the rack was open when I was ready. Don't like it? Wait or squat at another time. Sorry.
By the same token, if I roll in and somebody is squatting I have no expectation that I'll get in to use it. It's not my turn and I'm not entitled to its use any more than anyone else.
But that's just me.