not a milk at night kind of guy

The above statement is true...I'm not a milk at night kind of guy. I pretty much only have milk with cereal or spaghetti. But frankly, my milk drinking habits is not the point of this post. It's simply how the real point came up. Let me explain. The issue came up the other night when I was thirsty before bed and didn't want water. Polly told me to have a glass of milk. I proceeded to tell her that I'm not a milk at night kind of guy. Polly then brought up the fact that I always use the phrase "I'm (not) a ____ kind of guy" or when speaking in first person plural I say "We're (not) _____ people." Polly thinks it's a weird phrase to use and seems a little annoyed by it. I, on the other hand, think it makes all the sense in the world. And to be honest, I didn't even realize I do it. Am I crazy when I use these phrases or are they really completely normal. I tend to think they get the point across and let's face it...I'm a getting the point across kind of guy!