I have had good experiences with the Tim Horton's in the international and domestic areas (can't recall transborder). Quick, prices not inflated, you know what you are going to get.
Other than those, yes, I agree - especially the godawful "Irish" pub in the T3 international area - have never had good service in that place, dreadful! The new ipad places just seem like an excuse to cut wait staff down even more - they do not enhance my experience!
In the T1 domestic area, there are a few more 'grab and go' food options these days, there is decent pizza (I have only done the take out version, not the sit down Italian restaurant part), and Thai / Chinese food (Thai Express possibly?) The overpriced soft drinks bug me tho!