Why does it seem to be that security guards don't really want to do what they're supposed to?

It seems that whenever I go to malls, shopping centers, or private buildings the security guards don't really care to be there. I'm not saying that all security guards are like this, but a large number that I've seen have acted this way. Sometimes when I see them walking around they're just lugging around, and twiddling their thumbs. One time I was working in a shopping center, and one of the security guards came into our store to talk to us. She wanted to notify us that she was part of the new guards that were transferred in. This was a very nice, and professional act. One thing was a little off though, when she was talking to us she was VERY unenthusiastic. Later that week we saw her just moping around. Sitting on the benches, texting on her phone, and staring out into the distance. Things like that make it seem like they REALLY don't want to be there. I know that not every guard is going to be the most jubilant person in the area, but it would be nice if they were more active in patrolling the area. 

Security guard tour systems would be a great way for them to become more involved in the area, and not just sitting at their post texting friends. 

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