A handwritten thank-you note is a great way to show appreciation to your boss, or anyone.
When you receive a gift, send a thank-you no matter who sent the gift and no matter what the gift is. Email isn’t the best way to do this but it’s a great deal better than no note at all.
Civility makes the workplace more pleasant.
In some cases, it’s good to write a thank-you note for a thank-you gift. Email is okay for this.