bad friction is when 2 things rub together .
Friction is good because it provides traction. Friction is necessary for people to stand, or for vehicles to accelerate or break. Friction can also be used to convert kinetic energy to heat or electrical energy. Friction can be bad because kinetic energy is can be lost to friction.
Friction is actually not helpful to runners on a sledge, as it can slow down the motion of the sledge. To make the sledge move faster or smoother, reducing friction between the runners and the surface they are sliding on would be more beneficial. Lubricants or smoother surfaces can help decrease friction and improve the performance of runners on a sledge.
It depends what you want to do with it. Friction generates heat, which can be good (if you are cold), or bad (if you are not). Friction slows down movement, which can be good (if you are about to crash into a tree with your car), or bad (if you need high performance in an engine for instance).
Friction can be either good or bad depending on where it is. Friction between parts that are meant to stay put is a good thing, friction between parts that are supposed to move is a bad thing. Tires for instance are meant to roll along the road, not slide. Here, friction is good. But then you cone to the hubs. In here, the wheel has to move around the axle. Here, friction is bad. Here, friction will turn effort that would otherwise have gone into moving the bike forward into heat, which is no use to the rider at all.
Between the runners and the snow.
Friction
Friction is good in situations like walking or driving a car, where it provides traction to prevent slips and skids. Friction is bad in situations like mechanical parts rubbing together, where it can cause wear and heat generation, leading to inefficiency and potential damage.
Are fast runners good swimmers
Friction for a bobsled can be reduced by using materials like PTFE on the sled's runners, which have low coefficients of friction. Keeping the runners smooth and well-maintained also helps reduce friction. Additionally, minimizing contact with the ice by using a thinner sled design can further decrease friction.
For us, it would probably be bad. Without friction, it would be nearly impossible to get around. imagine walking around on ice all day, but worse.
Friction isn't always bad, but when engineers try to avoid or reduce friction, it is because of the energy lost due to friction.