Well you want
- bank that doesn't charge you for using your card abroad (like Halifax does - £1.50 for buying online apps in USD, 99 cent android app with 150% scrooge levy)
- bank that charges over the top for "overdraft" you never requested just because their banking system conveniently doesn't have a method of saying "no funds available" when you pay for your shopping in local supermarket (Halifax charge £5 a day for providing funds when your account doesn't have funds, whether you want it or not)
- bank that doesn't charge for banking (like HSBC does to new customers)
- bank that does't charge others for using their machines (like Alliance & Leicester does in some places, it will create backlash like in nineties - it only take one louse in a banking system and they all start charging £1.50 for withdrawing, we've been through that twice already)
- bank that doesn't charge stupid money for transfers abroad, (HSBC whacks their customers with £30 tax every time they want to transfer funds to account abroad)
- bank that won't help themselves to your funds when they feel your credit card should take priority over costs of living (Natwest were famous for years for it).
All the above might seem like "I don't need it now" scenario, but believe me, you will change your bank maybe once in your life, so you want to choose the least scoundrel institution here and now, if not for your own convenience, then at least to not support douchebaggery and others misery with your money.