I've also noticed English speakers leave out "the" in certain sentences. Like "She's in hospital" instead of "she's in the hospital" or "I play piano" instead of "I play the piano".
Seriously, this is deliberate because the answer is not specific: "in hospital" is a predicament, not a location. "I play piano" is a statement of fact about accomplishment - any piano will do. I do some proof reading of translations from Polish and constantly knock out "the" or change it to "a" as necessary.
More obscure is the southern English phrase "going (up) to town" - this means London - which is a city.
I don't know how Poles get on with this phrase - but it kills the French:
"the synthesizer is over there".