Ok ... let's kick this off with som clarification. I do not only have a 50mm lens. I also have a 100mm macro and a 10-20mm wide-angle. And yes that's all.
But if I rummage through my lightroom collections the data is clear: of all my 70.000+ images, more than 50% of them are shot with my beloved 50mm lens.
And I will try to show you some variety in doing so ... remember, I sad try!
#1 Depth of Field and Bokeh
Right off the bat I think the number one reason why I use it so much is the Depth Of Field (aka. DOF)
When shooting portraits you can get the most fantastic DOF.
I should mention, that I have the Canon EF50mm f/1.4 USM lens.
And as you can see the bokeh is fantastic as well.
The next thing I really like is sharpness. BOY this is lens can produces sharp images. Sometimes I'm really afraid I'll cut myself just watching the images. That's how sharp it is.
And this being the f/1.4 it shoots at its best at f/2.8 ... which happens to be my favourite – both in DOF and sharpnes ... lucky me :)
Now ... with the relatively small images we use here this might not render correctly, but I'll try anyways.
Well, I hope you get the idea.
#3 Variety and "closeness"
I rarely feel limited with my 50mm. I use it to shoot portraits, landscapes, houses etc. And my feet are often my manual zoom. And that manual zoom gives me an other advantage. I need to get close to my subject. I really like the "closeness" I get with my subjects – people in particular – when I'm forced to get close. Now this of course is a barrier as well ... being the somewhat introvert person that I am. But it is a great learn for me ... getting close to people. And once they get comfortable with me being close (sometimes very close) I feel I get better shots.
On the other hand, the 50mm sometimes sets me back. I simply can't move closer to everything. A ruin on an island in a Scottish Loch, I simply can't get any closer to, than what my daily preference of wet clothes is.
All of the above are shot with the 50mm. Now ... I hope this demonstrates a bit of that variety I think I can get, even though I "just" have the 50mm.
Niels is on Twitter as @steinmeier