Iran's capital is vast, crowded, vibrant, hot and dry. It has huge traffic problems, mad driving, incessant noise and bad pollution. Shops and bazaars everywhere. Mainly modern concrete-ugly architecture. Tehranis, however, are pleasant and friendly, and appear busily involved with the economic imperatives of modern city life in a way that seems strangely disconnected from the political and religious rhetoric of their leadership.
To even begin to appreciate what joys it must undoubtedly have would probably take at least a week, but give yourself a couple of days, and you might even begin to enjoy the place!