Why would a guy keep a drawing I made him in his pocket?

So me (F24) and my coworker (M26) have been friends for 6 months now, and there was one time at work I was bored so i drew a flower on a post-it and when I saw my friend passing by I gave him the drawing, I saw him directly put the note in his pocket and i did not think much of it since I know he puts all kinds of receipts and work notes in his pocket, but I also know that every now and then he empties his pockets (we wear a coat at work). Several months have gone by and I saw that his pockets are empty put the pocket at his chest had the note with the flower on it. Why would he keep this drawing all this time?

Why would a guy keep a drawing I made him in his pocket?
Post Opinion