It's not uncommon to leave an envelop for your room maid, tip a particular waiter/receptionist who offered great servive on your last night in hotel , or just leave an envelop for the whole staff by reception desk or with the manager. It's not obligatory or a must either.
Are bathrooms free in Greece?
Do You Pay for Public Bathrooms in Greece? Public restrooms in Greece cost money (around 50 cents). Most restrooms are fairly clean, but many of the toilets don't have seats so you'll need to squat over them. To be safe, I recommend carrying around some hand sanitizer in case the bathroom you visit doesn't have soap!