Instead of treating these people with contempt, and taking them for granted please treat them with respect. They do valuable work. Often work you would not do, but work you want done. 

Get off you phone when you are talking to them. If the call is really that important then take the call elsewhere first. Look at them when you talk to them. Call them by name (that is why they wear a name tag). Smile. Ask how their day is going and listen to the answer. Say please and thank you. Thank them for their service. Let them know you are grateful for the important work they do. Tip them when appropriate.

Take care.