Someone being so grateful over a good deed as small as this feels nice. It also feels lucky. Very lucky. Had he not happened to decide to turn this way when he had, that paper may have been lost to the wind. Ah well, no point in dwelling on unhappy hypothetical situations. "Not at all." Said once the paper has left his hand and gotten returned to its owner's.

After a beat, he adds, "You may wish to invest in a folder to keep such valuable documents more secure in the future." This isn't said in a scolding tone, but just as more of a suggestion than anything, with perhaps some underlying teasing hidden in there. Going off the reaction, whatever these papers were, they were of great importance to him and losing them again? Would be bad.