Paralysed by "what if"

The Archbishop of Canterbury, during his recent address at St. Luke’s, Maidstone, talked about the Bible passage from John 5: 1- 18 which recounts how Jesus healed a paralysed man at the Pool of Bethesda.
Some early writings report that at certain times the water would be stirred up and that tradition had it that the first sick person to make it into the pool when that happened would be made well. It certainly seemed a popular belief at the time, as John reports that the pool was a place where a great number of blind, lame and paralysed folk gathered.
Jesus spoke with one paralysed man who had been ill for 38 years and we read in verse 8 how Jesus healed him.
Dr. Williams began by challenging us with the question that Jesus asked the paralysed man (verse 6), 
“Do you want to get well?” 
and I was struck by the answer the man gave (verse 7), 
“I have no one to help me into the pool when the water is stirred. While I am trying to get in, someone else goes down ahead of me.”
I was trying to imagine the situation and thinking about that man, lying on a sleeping mat some distance from the water, so that when the water was stirred he couldn’t drag himself to the water quickly enough. I wondered why he didn’t just lie closer to the water’s edge – that way, when the water was stirred he need only roll himself into the pool – he wouldn’t need anyone else to help him at all!
But if that was possible, why was having help from someone else so important to him?
Perhaps, being paralysed, he couldn’t swim – in which case, I guess he would want to be very sure that he would be healed when he rolled into the water… and maybe that’s why he wanted someone to help him… as back up – just in case it didn’t work! It’s just as well that Jesus did come and speak to him because it doesn’t sound like the situation was likely to change any other way.
Which brought me back to Jesus’ question…
I wonder how often we miss out on amazing opportunities because we’re too concerned about the “what if” questions?