The coastal cities of the world exist primarily because of trade. Deep ports, access to waterways that were the ancient highways of trade, the housing to accept an influx of immigrants and the jobs to give those people an income all contribute to a virtuous cycle of urban growth. Coastal cities have a lot in common, but they also have a lot that makes them different from each other.
Timing is part of what sets coastal cities apart. While Manhattan was colonized, just a few miles to the north, City Island was established as a rival. It never really worked out, and now City Island is just a neighborhood in the Bronx, part of New York City. Similarly, Miami had a long history with trade in the Caribbean, including piracy, but it wasn't until the 20th century that it really took off, giving it a much more contemporary vibe than say, Boston or Philadelphia.
Geology also plays a role. New York is mostly built on bedrock, allowing the willy-nilly building of skyscrapers, while San Francisco endures the slow leaning of the Millennium Tower, built on mud that isn't supporting it in the best of circumstances and could totally fail in an earthquake.
Finally, trade and culture form the bedrock we experience the most. Boston sports several large universities, giving parts of town a young, hip vibe. San Francisco is the world's hub of tech businesses, making it the preferred home of many a startup. Chicago (on the coast of a great lake) is a transport hub with top colleges, stock and commodity exchanges, and a creative community.
Which should you call home? It's a matter of priorities. Take this quiz, and we'll help you out.