I endorse what MC Fat says about there being no pain during the procedure but nearly everyone I know who has had "the snip" had a problem later with infection. In my own case the swelling was quite dramatic (I wish I'd took polariod), "please can you take the pain away but leave the swelling?"
The worst part was encountering a very young and attractive nurse who was helping during the operation by holding my terrified member out of harms way while the doc did his stuff!
She was determined to make me at ease by chattering about the weather and what she was doing at the weekend while I desparately tried to ignore her and focus my mind on anything other than a pretty blonde smiling at me while holding my penis!
Oh yes, there was also the humiliation of being offered a sanitary towel to wrap around my testicles! I bet that nurse has a few laughs with her friends in the pub after work.