There's more than just one type of sweat, despite no types being desirable. Two types of glands produce two types of sweat.
The eccrine glands found on the hands, feet and forehead produce sweat that's 99% water and largely unoffensive. The apocrine glands, however - are found around the groin and arm pits. These are the main perpetrators when it comes to your unique brand of BO.
Depending on your situation, one type of gland will start working overtime. Here are some classic sweat scenarios.