The folks who refuse to merge until the last possible minute.
Really, it's not a construction thing, this is something that is just part of driving down this road, it goes from a four lane road to a two lane road. (two lanes going each way to one lane each way just before a bridge) and it's been that way the whole four years I've lived here, folks.
Which means please stop waiting till the LAST possible minute to merge? Traffic is going slow enough on that road today, we surely don't need anyone backing it up further because they're trying to get in and couldn't do it earlier!
And don't forget the people who get in the right turn lane that turns into a turn lane going into a parking lot instead of the second right turn (or straight) lane that goes into the right straight lane. Because so many of them are making a right turn, then cutting across two extra lanes of traffic (instead of just one) to get to the left turn lane (across from the parking lot entry) to get to a road that goes to two hotels, three restaurants, and a couple of smaller shopping areas....with an eye doctor, a dentist, and other specialty shops.
I'm turning right to go straight for two miles to get to the library & extension campus of a couple of colleges. I stay in the straight or right lane and I don't know how many people have tried to go through me to get to that left turn lane or in front of me to go down the street part of the way to the library...but if I had a dollar for every near miss, I could make a dent in my Christmas shopping list!
In 2000 until 2002, I was working where I drove home using an interstate highway that went from four lanes to two lanes after leaving larger town....and every single time, it seemed that the vehicle in the lane that was going away wanted to get in front of me, so they would keep going & going until they were on the shoulder honking at those of us in the continuing lane to let them merge to the right...when if they'd braked slightly at some point, they could have merged like a zipper. But they wanted in "at the front" instead of where they were in traffic already...
I see it a lot when traveling - no one wants to merge smoothly - they want to "jump ahead" of the rest of the traffic to minimize the time they spend, not realizing that they are the ones clogging the arteries of traffic and causing at least some of the slowdowns... Lots of the slowdown, if they cause an accident....