PRIMITIVE CHALK
The other sunny day I had the sudden urge to improve someone's day. I knew that it was finals week for the local college and wanted to make some inspirational art to get them through the struggle.
In the short time I was there, I had a wide variety of students and faculty thank me for making the campus sunnier and brightening their day. It cost me $3 in chalk and a short amount of time out of my day. Just goes to show you the power of a little primitive calcium carbonate :D
I now carry a few chalk sticks everywhere I go to save time from passing unoticed.