i do it almost everyday in a one lane street and most of the cars are stuck because they are waiting for a left turn. I just want to go straight. Some cagers have tried to block me, but they end up leaving the other side of the lane wide open. so I just go around them and just smile at them... lol...
Filtering in a single "line" situation is illegal, unless every car you passed was signalling left, and you had enough room. In a single "line" situation if you pass any car not signalling left you will be dinged with breaking 150 of the HTA.
If however you can argue that there is enough room for 2 "lines (not lanes) of vehicles, then you may get a pass, but you will have to argue it fiercely. Single lane filters are tricky, so be alert for the laws you may be breaking.
Also if any vehicle within 30m of the intersection is not turning left and is moving toward the intersection, and you pass them, in your own lane or not, you are also breaking the law (140).
Though many forms of filtering are not illegal in Ontario, some forms are, so take care. For example, in a multilane situation filtering in the left lane while cars are moving in the left lane is illegal 148(7)(b), while filtering in the right lane next to slow moving vehicles is not illegal (with the caveat it is safe and you have room) 147(1), 148(1)
Sorry for decending into a legal comment, as the OP intended this thread to be free of legal wrangling, but in all fairness some have already pipped in with the unbiquitous "it's illegal, I'll run you off the road" comments already. For those that think it is totally legal, it must be said it is not, and for those that think it is illegal in all instances, thus warranting their rage, it is not.
The issue of rage is attached to the principle of filtering, where the "budding" in line argument is more germane to the discussion.
As Rob stated, legal or not, cops let a lot of stuff slide, and if lax enforcement is the start of a cultural shift to the acceptance of filtering, than the point is valid....if it is not enforced, it is socially accepted, or on its way. The legality almost becomes moot in this instance.