Other drivers...
So, I am seeing a trend around where I live.... The speed limit is 55mph, the car in front of me is bouncing between 40 - 50 mph in areas where I cannot pass (double yellow or on-coming traffic). In areas that it is legal/safe to pass they speed up to 60mph, then drop back down to 45-ish in the no-pass areas. What the hell is up with is? I am not trail gating, until I am committing to pass I leave three - four car lengths between us. Then, when I get to where I can pass they'll speed up to where I am doing damn near 90 to get around them. Its not just me, a lot of people I work with have said that this is happening to them too. It is to the point were I assuming the jackass is going to speed up a lot when I go to pass, so I put my transmission in Sport mode and let my twin turbos do the rest.
Plain and simple - because people are ****ing assholes and have the "Me first!" attitude.
I love when people are in a hurry to pull out in front of you, often there are absolutely no cars behind, and then they go less than the speed limit.