In the situation when you have a lot of identical points to snap to you need to be careful when using object snap. And yes, sometimes you need to zoom in in order to be sure about snap accuracy.
At the same time for ENDpoint object snap sometimes it is enough to position cursor over the line and wait for a half of second autosnap marker to appear at right endpoint of the line, than you can just click with mouse button and you will get right snap- it is not necessary to move cursor toward the endpoint.

Maxim