A t-shirt dress in green is the easiest version of a dress you can own because it is just a longer t-shirt and nothing more complicated than that. Green works in t-shirt fabric because the casual construction matches the straightforward colour. The t-shirt dress works best in cotton or cotton blends because these fabrics are forgiving and comfortable enough to wear repeatedly. Oversized cuts work better than fitted versions for casual dressing because the relaxed fit makes the dress feel like something you just grabbed. Pair it with trainers and a denim jacket and you have completely accidentally dressed appropriately for almost anything. The simplicity is the whole point.