Listen attentively. Sometimes, all they need is an audience. Just give them a chance to tell their story and show that you are interested.
One way is to be polite but firm. Politely interrupt them and say you have limited time. For example, 'I'm really sorry, but I have to be somewhere in a few minutes.'
We can ask them directly for the rest of the story. If they refuse or are evasive, it's a sign that they might not be trustworthy.
One way is to confront them directly. Ask for clarification and evidence. If they are lying, they may struggle to provide consistent details.
We could also try to steer the conversation in a different direction. Maybe introduce a new topic that requires shorter and more concise responses. Like if they start a long story about their trip, you can say 'That sounds interesting, but have you heard about this new movie?'.
We can listen attentively. Even if it's the same story, it means a lot to them that we show interest.
We can try to ask them more specific questions to get the missing parts. For example, if they are talking about an event, ask for details like who else was involved, what time it exactly happened, etc.
We can just listen with a grain of salt. Maybe they just like to be creative and have vivid imaginations.
One way is to ask them questions. By asking for more details or different perspectives, we can encourage them to think more comprehensively. For example, if someone is telling a one - sided story about a relationship problem, we can ask 'What do you think the other person might have been feeling at that time?'
You can also set some boundaries at the beginning of the conversation. Say something like 'I only have a few minutes, so let's just talk about the main points.' This way, they know from the start that you're not up for a long - winded tale. And if they still start a long story, you can remind them gently of what you said earlier. It's important to be kind though, as they may not be aware that their long - story - telling can be a bit much for others.
One way is to simply ignore it. If you don't give him the reaction he wants, he might stop. Just continue with your own story or conversation without acknowledging his attempt to one - up.