When you think about someone entering MRI that picture causes negative response in your body. What a beautiful day and Im sitting here- just thinking for myself.

I was never in jacuzzi but when I imagine those bubbles I belive it feels good. If you remember how it is to be in jacuzzi and quickly remember guy in the tube that will be completely different experience than being short of breath. This example will not cure anyone's phobia but it can help you to understand on intuitive level how phobia or anxiety work.

"Phobia" in will give you tons of material for waisting time. In general there are two approaches: offical psychiatric, "you have to recite Homer in ancient Greek to cure phobia" and "curing phobia in one session by phone for 200$". It is important that they are cheap.