Settling one tile away from coast usually gives you 3+ coast tiles you cannot improve by a lighthouse, Moai statues, dike or whatever. Settling on the coast gives you access to lighhouse, harbor etc. and you can build ships. coast tiles may still not be as good as many others, but, especially if you are FIN they are not that bad in the earlier game, with the additional boost of trade routed by harbor, coastal cities are often quite decent, although in the long run, grassland cities will of course be better with cottages or workshops.
So I usually either go for coast or for two tiles away to avoid any coast tiles, if possible. Of course there are exceptions and many cities are settled with 3+ desert or tundra tiles, just because it is unavoidable, so clearly there are worse locations than 1 tile frome the coast.