There are numerous ways to show that you're a responsible adult. Inbox Zero is one. Eating your veggies, voting, and wearing your seatbelt are others. Remembering to send a card? BINGO! Perfect for saying "thanks", "congrats", or basically anything else you get your shit together enough to send a card for. A2 size, blank inside and comes with an envelope.
Ladyfingers Press Responsible card