A graph is a set of objects plus the relationships between them. Whenever your problem is really about connections, a graph is the natural fit. The objects become nodes, and each relationship becomes a link joining two of them.
It models more than you might expect:
Road maps, where intersections connect by streets
Social networks, where people connect by friendship
The web, where pages connect by hyperlinks
Task schedules, where jobs connect by "must run before"
The payoff is that one toolbox then applies everywhere. Questions like "can I reach here from there" or "what is the cheapest route" become the same search over any of these. You stop writing bespoke logic per domain and reuse proven traversal instead. That reuse is why graphs show up in routing, package managers, and recommendation systems alike.
Rewriting in plainer words…
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