I personally don't take on private work. Because going to work is already tiring. My feeling is that the rewards of putting in a good shift are greater.
But some people take on private work as a hobby, or a way of life.
Meet a lot of people inside investment banks and banks who come out and teach a couple finance classes a year. That is, they put their specialties to use, review their knowledge, meet new people, and make some money. What's not to like.
In contrast, some people work as yoga instructors. Some people are going to be wedding photographers in their spare time. I think these are all fine, as long as you are busy and have fun doing it.
Purely for the money, I think it's not very interesting. But it also depends on the individual. Some people do not receive high income from their jobs, but they can find a little opportunity to do some private work, and their income from private work is higher than that of their own business. This becomes the norm in life.
This is not good to oppose, because everyone has to eat is not.
I personally tend not to dig the company corner. Or you temporarily dig a dig, the return is really good if. But also have a long-term plan.
Again, I'm against the example.
I have a relative, the child is twenty years old, just graduated, found a very bad job, do not like. At night her mom told her to waitress in a restaurant. I fainted when I heard that.
In my opinion, such a flowery age, life has endless possibilities, not satisfied with the work, there can be a lot of other ways to go, work idle nothing to do, can be used to study, the examination certificate, spare time can be on the class, to know the level of the higher level of people. All of these things are much better than going to be a waitress, this amateur income, honestly give me I do not want. I don't think it's worth it.
Lastly, I would like to summarize my point of view:
To do private work, consider the 'short-term return' and 'long-term impact', just like buying real estate, think about whether the land will appreciate in the long run.
Both are positive, doable.
One is negative, doable in the short term, don't do it in the long term. Temporary small money is of low importance in the long run of life, or so I thought.
Both are negative, you won't do it, needless to say.