Had to pay rent: $395

Had 400 dollars in $20 bills.

So $20 x 20

Needed change to give him $395.

So he gets change for a $20 bill.

$10 x 1 and $5 x 2.

Now I take his money and keep my $20.

So I give him $20 x 19 and $10 x 1 and $5 x 1. For a total of $395.

I leave and go on my way with $20 in my pocket. Then I totally forgot I didnt take the 2 $5 bills for the change for the $20. So I go back for them. Now I have $20 x 1 and $5 x 2, a total of $30.

I think to myself this is too much money. And when he counts the money there is $375. I'll note that when I came down initially for the $10 dollars that he already had it stashed away and didnt seem like he was going to return it. So I gave him a $20 dollar bill for a total of $395. I had $5 x 2 in my pocket.

Then I realized I should have more. So I went back down to get an extra $10 back. Now I have $5 x 2 and $10 x 1 for a total of $20.

So I dont know what happened and I'm sleep deprived and cant think so with that said these are likely the scenarios:

A) He took the $20 bill for himself when I forgot to take the $10 in change and out the $10 in the stack, hence why there was only $375 when I went back for them.
B) I was supposed to give him $5 dollars back when he gave me change, regardless if I forgot to take the $10 I forgot.
C) I was right the first time and am stupid, and just ended up giving him an extra $10 dollars in our final interaction since I have $20 now.

--- I also wasnt sure if I had a extra $10 and that is contributing to the $30 I had originally. ---

Please, I cant stress my brain any more in this state.