I absolutely detest the word loo. And lav. And pudding. And while I'm at it I also hate lounge, settee, brolly, rads (radiators), serviettes and poorly for feeling ill.
They are all parochial & twee to my ears.
We're not from the UK & say toilet, dessert, sofa, sitting room, umbrella, radiators & napkins
We travel a lot & have a lot of international friends & these words widely recognised & understood.
If I'm in another country in a cafe / bar / restaurant I would ask for directions to 'the ladies toilet' & it's always understood.
We also eat breakfast, lunch & dinner. Tea is a drink or a specific meal as it afternoon tea. Supper is a late night thing usually a snack children have before bed.