Here’s my guess. They don’t want to pay attention to the Be Careful Who You Hate It Could Be Someone You Love T-Shirt But I will love this other vehicles merging. They probably aren’t comfortable being in the middle lanes because of too many vehicles around them. The far left lane is furthest away from the “chaos” of merging vehicles. Once they are in that lane it’s their comfort zone and they can relax a bit. Then they go back to doing anything other than paying attention to the road. I get really annoyed by this, but there are times when it’s justified. If there’s an intersection, left exit, or high traffic I don’t get too bothered. The people that drive in the left lane outside of these conditions are selfish, and just want an unobstructed path for themselves regardless of what is good for everyone else If you’re coming up on me going WAY too fast (anything over 10+ mph), then it’s safer for me to stay right where I am and avoid a rear-end collision.