Why should I buy a 50mm prime lens?

Challenge #5 in the Opportunities series. Hosted by juanlucas.
Challenge has finished
I made a mistake... haven't bought a 50mm prime lens yet. Show me why I should buy it!! MANDATORY to indicate brand/model of lens used for taking the picture (of course, only 50mm prime lens for this challenge).
Show full rules
submission
phase has
ended
94 entries
voting
phase has
ended
1944 votes
Zhivan
by Holly P
Click here for full size original image
85th place (joint)
1.925
 
low
high
Third birthday
Camera:
Lens:
Submitted: Tuesday, 28th June, 2011 05:19 (GMT)
Taken: Sunday, 18th April, 2010
Focal length: 50 mm
Shutter speed: 1/60 sec
Aperture: F2.8
ISO: 200
Notes:
Views: 129
Galleries:
Provide complaint details
Your complaint (along with the complaints of others regarding this entry) will be reviewed by the challenge owner. Depending upon the nature and applicability of the complaint, the entry may be disqualified. In extreme circumstances the user who submitted the entry may receive a ban from the challenge or series in question.
Reason:
Comments:
Saving ...
Complain
Keyboard shortcuts:
p previous n next c challenge f full size r retract vote # vote