Barcelona 1992 was my second Olympic games and, after the injury disappointment I faced in Seoul in 1988, I was determined to get it right.
In Seoul I was never settled in the hotel or the country and it totally affected my preparations. Every athlete is different but the time difference, the food, the noise, it all played its part to unsettle me.
Then I had to withdraw with an Achilles injury.
I remember when the closing ceremony was taking place I stayed in my hotel room on my own; I didn't even watch. I never felt part of it or like I deserved to be there.
So I was determined to be a part of it in Barcelona four years later. I flew out to our base a week before everyone else, got settled into the hotel and felt good from day one.
As an athlete you have to get the little things right. Before anyone else had arrived I organised the rooms so all the noisy people were down at one end and I was right at the other.
If it makes you feel better, it will help, and the whole British team will have that benefit in 2012. The whole Games have been organised with them in mind.
I strongly believe that having the Olympics in their home country will be a huge advantage for our athletes. To be in London will be a massive boost - our athletes will feel at home instantly.
I felt good in Barcelona and I was running really well. I remember clocking 45 seconds dead in the heats without even trying and it had never felt so easy. So I was running for a medal, no doubt about that.
My hamstrings felt a little bit tight but nothing out of the ordinary. As a sprinter you get used to it after a few races in the space of a few days.
In the semi-final I got out of the blocks well but after 150m or so it felt like I'd been shot in the back of the leg.
The physical pain was intense and that was all that was in my mind for the first few seconds or so.
I got up and I honestly thought I could catch the rest of the runners and still make the final. Even when they were going round the final bend I thought if I started running I had a chance.
But I could barely walk.
There were some medical staff running over to me with a stretcher and ushering me to get on to it - but I just wanted to finish the race by that point.
It wasn't meant as a grand gesture or to prove the point that it is the taking part that counts. I never believed that and I don't think any athletes do. If I didn't think I had a chance of winning then I wouldn't have put myself through it.
It was then that I became aware of my dad running over to me.
He tried to talk me out of it at first. He was telling me that I had nothing to prove and that I didn't need to do this, but I told him I was going to finish. Then he said that we would do it together.
So we did, and I limped over the line in tears.
I wasn't aware of the crowd's reaction at that time; I wasn't really aware of anything at that point.
It was only after I had had some treatment on the injury and left the stadium that I saw all the press waiting for me. I didn't want to talk but agreed to hold a press conference the next day.
I was expecting a handful of reporters but the whole room was packed out.
It obviously captured people's attention and I have been very lucky from that day on. It could have gone one of two ways: people could have taken it as they have or they could have thought I was an idiot.
That was me done after that. I had about eight or nine operations but I was never fit enough to compete again.
Of course I wish things had turned out differently, but I had the chance to run at two Olympics and I'll never forget it.
Derek Redmond was talking to BBC Sport's Tom Rostance.
By Derek Redmond