My coworker and I shared a stamp that we got made for this purpose and it became something people looked forward to getting in their card, weirdly.

I think it said something like

Dear ______,

Happy Birthday / Anniversary (circle one)

You are such a _________ and __________ man / woman (circle one) and I hope you have a great day.

With utmost sincerity, Name

Something like that. I think I actually still have it somewhere.