Landlord asked for the first month's rent in cash. I went to the ATM, took out 3 million COP in mixed bills (the most cash I've ever held). Showed up at the apartment ready. Landlord looked at the cash, looked at me, said "we have to go to the bank to deposit this, I don't keep cash."

Spent 2 hours in line at Bancolombia, depositing my own money into his account. Could have just done a transfer. Lesson learned: always ask "transfer or cash" and pick transfer.