Merging and changing lanes is often a problem.
You're supposed to turn your blinker on for three or four seconds before changing lanes, but all that does is give the driver behind, time to stand on the throttle and move up to block you out.

It's just so common that I've made it my usual practice to move up next to a gap, then put on my blinker at the same time as I move into the next lane.
You've even got to be careful not to make it too obvious that you are eying off the next lane.
Even if some drivers just get the impression you're thinking of moving into
'their' lane, they bunch up like they're playing bumper cars or something.
Just plain rude!
I suppose the upside of that is, on the occasions that someone actually pulls back and waves me into their lane when they see my blinker on, it really makes me feel good.
I give them a happy smile

and nice wave, and feel happy,. right up until the next prick blocks me out.
And yes, in case you're wondering, I always move back to let peolpe in, sometimes to the annoyance of the driver behind me who was already bunching up behnd me expecting I would do the same.