I was always told that the young, fresh, 1000 hour CFI turned RJ pilot's were the worst. I tend to notice they are one of the cleaner groups. There is this stigma about backpacks, ear buds and hair gel but I have seen only a VERY few select like that at my airline (and just walking around the airports).

The biggest offenders I actually see are the younger to middle aged 4-stripers. They have he back packs (but I'm an FFDO!), no ties (or half tied tie), ear buds (or worse... Beats headphones), and a shirt that looked like the rolled it up in a ball and drove over it with a steam roller.