A hem can change how confidently somebody walks into a room.

Clothes that fit properly stop asking to be managed, and the attention that was going into tugging and adjusting is freed for whatever is actually happening in the room. An inch of fabric is a small thing to change and a large thing to feel. This is why alteration is rarely vanity: it is the difference between wearing something and negotiating with it all evening.

If a garment you own is nearly right, have it adjusted rather than replaced. And if someone quietly does that sort of work for you, say so, since it is easy to enjoy the result without ever noticing the hand behind it.