Is it true that some British don't like Americans visiting their country just because of their manner when using the toilet?

I never heard of such a thing. And i barely would believe that, it's a ridiculous statement! Every cultural thing would convince me but using toilet ? Most of European countries and U.S and even Asians like Japan are align with the same toilet culture, about the usage, the system, the equipment ect . . .

But what's the thing! British people sing poem when they go to bathroom and we don't !!!!! ? Gimme a break!

I have no idea what "their manner of using the toilet" even means.  I know that some British folks wonder why Americans call it the "restroom" or "bathroom" instead of toilet though.  I have a feeling that might have been misconstrued into what you heard.  It's all just so silly.

No, that is nonsense.

On a slightly different tack, I remember being told on my first visit to the US about how they believe they are perceived as "ugly Americans" - supposedly noisy, brash and having too much money.

This was news to me, since the only Americans I had ever met had been friendly, polite and downright "nice".

The US gets a bad reputation (as do we, here in the UK) for their foreign policy and their "interventions" around the world.

As ordinary people, Americans are usually well-liked in all of Europe (except Paris).

We're all the same really.