I've been third-to-last in several races, but not been made to feel bad about it. In my first 50k when I was third-to-last (but didn't know it), the aid station folks were still there and in fact toward the end they were radioing in my position (and presumably also the runners after me) because the race director wanted to make sure to know where all the runners were - but that was a trail race - see below.
After reading some of these comments, I'd suggest some of you consider trying trail running/racing. Trail runners are much, much more mellow about the idea of running "fast" and what pace people are running (even though some of them are in fact really fast). It's so much more about doing your best and getting out there.
Because of the terrain and hills, trail running is also naturally run/walk. You walk the uphills, and lots of people walk the uphills. As you get better, you can start to run some of them, but there are always hills that everyone ends up walking, especially in a longer race.
Trail races are much smaller, so yes, there is more of a chance of finishing toward the end, but absolutely no one cares. In my first 50k (referenced above), I "ran" into the race director in my last few miles (the course had lots of crossing paths, so he was picking up signs from parts that really didn't have any more runners), and he ran to the finish with me.
There are trail races of all distances, from 5ks to ultras, so you don't have to run long to run trails.
I realize that for a lot of folks it can be hard to find natural-surface trails to run on, so that can be a downside. And you don't want to do a trail race without some experience running among rocks and roots. But if you have the opportunity, it may be worth trying. The trail running culture is so different.