US resident here. On the local freeway, when I signal I wish to make a lane change, other drivers often speed up. I really don't get it. What did I do to their family?
The trick is to follow the mirror, signal, maneuver method. In other words, you don't signal until you know you have a gap to change lanes into. If you signal first without checking for a gap first, then you're treating the signal as a way to ask for permission to change lanes. Other drivers may or may not allow you to do so.