Diplomats and military commanders in Afghanistan have a hard time explaining to the politicians back home how Afghanistan operates. In short, most Afghan leaders are corrupt (by Western standards). Most Afghans are quick to violence and tribal, ethnic and religious affiliations are more important than national ones. Over 70 percent of the population is illiterate, and the population is generally hostile to strangers Including fellow Afghans. The best known clean government movement in the country is run by the Taliban, who are also into Islamic global conquest and the support of Islamic terrorism.
The Taliban have embraced the use of terrorism to intimidate opponents (mainly the national government and tribal leaders). After years of resistance, the Taliban have accepted the use of suicide attackers. This tactic is an Arab thing, that was long opposed by the Afghans. But decades of Arab supported religious schools in Pakistan has produced young Afghans indoctrinated to accept the concept of suicide tactics. This, and the widespread use of landmines and roadside bombs was found to be more effective in causing casualties among foreign troops. Afghans fighting foreign troops usually ends in disaster (for the Afghans), so the Afghans concentrate on Afghan security forces. However, these can also be hard to handle if they have been trained. For all the talk of "Afghan warriors", most Taliban are untrained, but eager, country boys with guns.
Pakistan has become less hospitable to the Taliban in the last year (the Pakistani Army invaded the tribal territories because of an Islamic terrorist offensive against Pakistani cities and leaders), so many Taliban who would have gone to Pakistan sanctuaries for the Winter, are staying in Afghanistan this year. This means that these groups of gunmen can be found (they are generally not welcome in Afghanistan) and attacked. Thus there is more Winter combat this year than last. The Taliban usually take heavy losses.
The surge offensive this year has used a third more bombs and missiles (about 500 a month) than last year. In the last few months, American Special Forces alone have arrested about 800 terrorism suspects a month, and killed 320. These losses are usually inflicted via raids and exploiting intelligence. The special operations troops are hurting the drug gangs, who are protected by the Taliban, and this makes a lot of Afghans (about ten percent of the population) who made a lot of money from the heroin trade, unhappy with this aggression against drug operations.
The Taliban is consistent in some respects. For example, they are still hostile to foreign aid, seeing it as dangerous foreign interference. At best, the Taliban will tolerate foreign aid if cash, goods or services are given to the Taliban in the process. The drug gangs don't like the foreign aid workers, because too many of these troublesome foreigners are hostile to the drug business. Can't have that.