Unless they start acting like Vodafone I couldn't give a crap if their colour is blue, red, green or a sort of mauvish-pink.
Get proper contracts with enough data for a person in the 21st century. (Or at least the 20th) Like Vodafone
Match your prices with Vodafone's
Offer the same service as Vodafone (ie sales people who actually have heard of the phone you want and don't look at you like you're from Mars if you ask for a Class 4 MicroSD card)
Let us actually try out a phone before spending a whackload of our increasingly hard-earned money on it, instead of a plastic/cardboard cut-out. Like Vodafone.
Then also, let us return the thing if it suddenly stops working while under warranty and give us a new one, finish and klaar. None of this waiting seventeen months just to be told it can't be fixed bull****. Like... well you know...