The difference is in your reaction to loss. If people spend a few dollars on the lottery, most people are not going to be upset when they lose. Of course, they

The difference is in your reaction to loss. If people spend a few dollars on the lottery, most people are not going to be upset when they lose. Of course, they're are always people who spend everything they have on gambling, but most people agree that a lottery is something you expect to lose. When people invest, they don't expect to lose. Of course course, there is always the risk of losing, but the difference between a lottery and an investment is that there is an expectation of loss in the former case.