After having received some genuine payments from friends, my only bit of feedback not already covered would be to allow for the payment to be categorised.
My real world use case for this has already happened. I’ve made a deposit to a restaurant to cover myself and friends deposits in total and this payment is correctly categorised as Eating Out. They’ve repaid me through monzo.me but because I’m not able to re-categorise the payments from friends and therefore my Eating Out target for the month is already exceeded.