I thank them every time they do it right: look at the badge, look at my decal, and look at me. I really respect the guys who call me by name - it shows that they just didn't glance at my badge, they really read it.
I even thanked the guys who did a random search of my car with a dog one time. It made me late to a meeting, but everyone in the meeting felt safer knowing that there is actual security at the gate, not a token like mouth breathing RC thinks the security is.
Once in a while there a guys at the gate who don't leave the shack, and wave me through while I'm still 10 yards away. I realize it's cold, boring, and low threat, but it is still their job. There are maybe 2% of the gate guards who are giving RC the ammunition to spew his assinine vitriol.