A grey sweatshirt and grey sweatpants are the kind of a never-failing casual combo that you need when you have zero time to put together an ensemble. Classic and casual outfits for stylish guys in their 20s aren't actually that hard, as you can see here.
Grey Sweatshirt with Grey Sweatpants Smart Casual Warm Weather Outfits For Men In Their 20s
Such items as a grey sweatshirt and grey sweatpants are an easy way to introduce understated dapperness into your off-duty repertoire. If you want people to see maturity in you as a 20-something man, an ensemble like this is what you're looking for.