Because of double booking or ill-health I hate missing out on anything. I can’t imagine how terrible Thomas would have felt by missing out on the first appearance of Jesus after His resurrection. When he met the others they would all have been bursting with the news. They had actually seen Jesus alive! Not having had the same experience Thomas would have felt completely ‘out of it.’ This may have explained his outburst.
When Jesus did appear a further time Thomas was there and specially included by Jesus. How embarrassed he would have been when Jesus made the offer. ‘Put your finger here, see my hands.’
Do we sometimes say to God ‘If only this or that would happen, I would believe?’ We can’t treat God like that, we can’t bargain with Him.