6. The Boor – The saying "A person who is nice to you but is not nice to the waiter is not a nice person" has been slapped on posters and can be seen all over Pinterest. But as trite as it sounds, it's true. When you see your guy act dismissive, abusive or disrespectful to someone who works in a customer service industry, such as waitstaff, cashiers or even telemarketers (though we get that it's hard to be nice to those callers) it usually means that he feels "those people" are beneath him.

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Raytheon CEO Bill Swanson wrote a booklet called Swanson's Unwritten Rules of Management, and in the booklet, he writes, "Watch out for people who have a situational value system, who can turn the charm on and off depending on the status of the person they are interacting with. Be especially wary of those who are rude to people perceived to be in subordinate roles." Take notice when a guy completely blows up about minor infractions, like cold food or a spilled drink, that a server easily can fix. A nice guy will help the server feel at ease and will compensate him or her for a job well done, not berate him or her for not meeting his unreasonable standards.

That hypercritical attitude can leak into his relationships with others, including you. It may result in you feeling like you're on pins and needles, waiting for him to make much ado about nothing. Perhaps he was not raised with good manners – if you decide to have a child with him, do you think he'll teach your child any different? Perhaps he feels like he's not in control of his own life, and he must compensate by controlling others and being disrespectful. Regardless, the feelings that lead a person to treat those in service roles badly are not feelings for which you want to be on the receiving end.