I don't know if these ought to warrant the GGG but I have noticed a couple of annoying habits guests sometimes have.
a) if the reception asks you to fill in a check in form, please fill it all in. Hell, make stuff up if you want to - but dont write your name, sign it and say 'is that enough?'. In a lot of places the hostel/hotel has a legal obligation to collect a few details about you.
b) dont ask for discounts or discounted group rates for no reason. 3 people for 2 days is not a 'group' and I have no idea who you are or what you're like, why would I give you a discount? a lot of places alter their prices according to season etc, we're not just going to change them because you asked - and especially not if you ask by email.
why yes, they DID both came up just recently, why do you ask?