A phobia is an ongoing fear about a particular object or situation.
By avoiding these things e.g. going in a lift, people who have fear or phobias actually make them worse.
When you are in the presence of the feared object or situation, you feel extreme distress or, you may even have a panic attack.
While most people don’t particularly care for poisonous insects or close spaces, if you have a specific phobia, you will probably be worried in anticipation of encountering your feared object or situation and the fear is out of proportion to the risk.