I'm usually very careful about buying the freshest stuff, but then will use it long past the date.

1. Fluid milk--I can just get through a gallon of skim by 5 days past the sell-by date. About 1 gallon in 10 I have to throw some away (usually b/c of travel or something)...my normal b'fast is cereal/milk
1a Eggs--I'll buy the freshest and then use them up for months (literally) past the date.
2. Cheese--I'll keep it unopened way past (6 months for cheese, in actuality) but watch it carefully after opening
3. Soda pop--I frequently see expired diet soda. After a disgusting experience at a mini-mart, I'm very careful especially with specialty flavors. Not good especially for diet to sit around in hot/outdoor conditions
4. Preserved meat/bacon--usually I'm fine with a month after the sell-by date as long as unopened and vacuum is left good (I did just yesterday toss an unopened lb of bacon with a June expiration date)

Farmer Jack (A&P) in our area has a "bounty" if you see expired stuff on the shelf and is very rigorous in the deli/fresh area. That said, they do slip from time to time and are less good with dry groceries at the urban stores than in the suburbs

Best situation I ever saw was an international market in St. Louis (Global Foods on Kirkwood Road in Kirkwood...BTW if in the neighborhood it is a wonderful place to visit). It's in about a 20,000 s.f. old A&P that is truly immaculate. Absolutely no "international market" odor, extremely clean and tidy (almost clinical) and literally every ethnicity known to mankind has food there. For the European (generally) products which are labeled with dates and move slowly, they are scrupulous about reducing prices to get them out of the store (interesting it seems to be generated by their POS system)