So.........You've done this before too huh ?
Oh, and loud ? Leave that up to the Brits. They're really good at it.

But seriously, don't be the loud, obnoxious American. For a lot of different reasons. Not the least of which is that if you're quiet and you blend in, you're a much smaller target.
As far as cash vs credit cards and ATM's ? A few short years ago, you'd have to call all of your credit card companies and give them "travel advice" (where you were going, when, for how long, when you're returning, etc.). Now, you can cover most of that online. We use our AMEX's a lot over there. AMEX doesn't care where in the world you are, you don't even have to notify them that you're traveling out of the country. They're the "Easy Button". ATM's are plentiful and work just like here in the states. And, pretty much all of them have "Englisch" as a language selection. Some don't, but they're not common and it's not too hard to stumble/fatfinger your way through the menu.
If using an ATM, you should have a debit card from a (your) bank that does not charge exchange rate fees. Provided that is the case, use that card to withdraw cash from the ATM in the local currency (Euros, Francs in Switzerland) and ALWAYS select the option to have YOUR banking institution handle the currency conversion cost (at no cost to you). There is very little, if any reason to use any currency converters/traders (like you see in the airports). You'll pay a hefty fee if you use them and pretty much for nothing that you can't already do yourself. We actually don't carry much cash over there, what with the easy availability of ATM's. Like here, most/many transactions are via debit or credit card. But, as I think about it, cash transactions seem to be a bit more common there, than here.
@Herb Stoner; Where'd you live over there ?