I am a person who enjoys writing thank-you notes- specifically hand-written thank-you notes.
I didn't used to; when I was a child I resented the hell out of my mother making my brother and I write them. None of the other kids had to write them. But then I became an adult, and the habit was set, and I found that I was no longer doing it out of obligation; I was doing it because it made me feel good to do it.
Therefore it should come as no surprise to you, Gentle Readers, that after my baby shower I very promptly sent out appropriate little thank-you cards to each giver (even tho' strictly speaking, etiquette dictates you need only send them to the people you weren't able to thank in person). What I'm realizing, now that I'm almost nine months into this whole raising-a-human thing, is that some of those gifts deserve a second round of thank-you notes.
Not, "Oh you were so thoughtful and generous," oh no. More like, "Holy shit you knew exactly what I would be needing, even if I didn't!"
Hooded towels made from adult towels, so they actually fit past the newborn stage. Tiny little rubber duckies that perfectly fit a baby's hand and can be used to distract/bribe during changing sessions. Board books that are well-written enough not to make me want to kill myself, but also short enough to get through at bedtime before infant-meltdown.
You know, the little things.