This as-told-to essay is based on a conversation with Ari Simpson, a 39-year-old entrepreneur from South Carolina, about her T-shirt side hustle. It has been edited for length and clarity.

Each fit brings its own flavor to the table, so whether you’re going for a sleek, body-conscious look or maximum comfort on a lazy day, there’s a t-shirt out there that’s up your alley.

It’s rare for this writer to get compliments on a plain T-shirt, but if this is the single-most tee that stands out to innocent passersby. We love the weight, the feel, and the fit, but ...