the thing is...

the thing is

The main or fundamental issue or element (of what's being discussed). I agree with your point, but the thing is, if we agree to increase spending for education, then all sorts of other public utilities will go underfunded as a result.See also: thing

the (only) thing ˈis...

(spoken) used before mentioning a worry or problem you have with something: I’d love to come — the only thing is I might be late.See also: thing