Commuting in Bangkok is tough and dangerous but the conception that taxis are recommended is wrong--in fact, being in a taxi and getting stuck in one of those famous Bangkok traffic jams can get frustrating!!
We did not travel even once by taxi during our stay in Bangkok, except for the airport transfers.
The sky train is the best mode of commuting, especially if it runs anywhere close to your desired point of travel. Buses are also very comfortable and the network covers the city well. For short distances tuk-tuks are convinient.
The people are like those in most big cities, always in a hurry, but most of them are nice and helpful. As is the general principle in a strange city, carefully judge a person before talking to him, because thugs are present here too, like in most cities in the world.