Fact: Every year quite a few tourists die from altitude sickness accompanied by a hired guides. This shows how corrupt the guide and trekking agency system is in Nepal. Tourists pay $20-40 per day but only few rupees are going to the actual guides or porters. Most of it goes to the head man. Guides then receive baksheesh from guesthouse they lead you too.
    Guides or porters are not necessary for all the popular treks because the areas are highly developed and not off the beaten track. It is like walking around any village in India or Nepal. These days a road has been built all the way to Jomson, you can take a jeep or bus, walking not even necessary. Never book in advance (never book at all.) Never send money to any agency from abroad. Beware of touts on the internet who charade as real backpackers, they happily hired 'Nirmal' the guide or porter, they will recommend to you in their fake blogs.

    Slow, uncomfortable more expensive than microbus or government bus. Tourist buses are run my private companies who use old and slow buses to slick tourist around. While paying 500 Rs for a deluxe bus to an agent the bus seat is actually only worth 125Rs.  They bus is the taken to various baksheesh-paying restaurant for expensive rest stops, wasting more time.  Beware that they may try to push tourist around to undesirable seats in favors of Nepali who just hope on for a short ride! Tip: If you are going Kathmandu to Pokhara there are micro bus that run locally and take only 4-5 hrs not 7-8 as the Tourist Buses.

    Is more expensive than bargaining yourself. Don’t be fooled by coupons or hotel deals at the airport (unless you want to try to get the taxi free! You can do this by pretending to be interested in the tout hotel and then take a quick look and then disappear!)
    The other way is to leave the airport and head out side and bargain for your self, you'll get a much better deal.

    Tourist internet charge can be high at 5-15 Rs per minute. Actually Nepali price is 2 Rs per minute. You'll see many Nepalese at the internet place too and wonder how they can afford it!
    Look out side the tourist bubbles and you’ll soon find local shops that Nepali use and who will charge you equally.

 Check the dates on packages water, chips, snacks etc. Many times the date is rubbed out! This is sure sign of a scam!  Also beware of fake or expired water bottles.  Be wary of fake good with substandard content such sunscreen. Anything that comes in a bottle or package

 Even the local buses may try to overcharge you. Ask locals how much they are paying, find out the correct fair. Don't get ripped off.

 Beware of the many “German Bakery” that offer substandard foods, even coloring their white bread with molasses to sell it as “Brown Bread” It is in fact no wholewheat but plain white, which they prefer

 Another dangerous activate they you may not be aware of it. Many tourists are injured in the risky thrill ride. Beware the medical facilities may be inadequate in Nepal should you have an accident. The Paragliding companies will not pay damages and have no responsibility in Nepal.

 Beware of NGO that want you to pay for volunteer work.  Many of the trekking and guide agencies have added volunteerism to their brochures. It is completely unregulated in Nepal and many trekking agency have developed this as a sideline.

 Beware that many youth may try to get a few bobs out of your. Just ignore them and keep walking.  They can't force you to donate unless they are armed. (I guess now that government has changed this isn't a scam anymore.)

  Riding the roof on the roof is very dangerous. Many people have been killed doing this. It is also common to overload the bus. Overload causes already old and unstable buses to become more dangerous.  If the bus must stop for a cow or another vehicle in front, people on the roof will fall off possible being killed. Remember in Nepal and India there is not responsibility by private companies and there is no legal system to make them responsible.

 Every kid in Nepal is now told to ask tourists for a sweet or pen.

  There are many agents that offer shipping services claiming to ship via UPS or DHL. They know that tourist usually do this the day before they are leaving (or you tell them!)  They simply keep your stuff and you are out of luck.
If you want to ship prcels back home take it to the Government post office yourself and get the paperwork. They offer insurance as well. Maybe a better option is to take it to Gorakpur or Patna in India and ship it from there.