Some people feel that doing a logo is a very simple task that they could easily engage on their own. They create a logo simply based on their ideas and concepts, but their lack of graphic design knowledge makes it look bland, rushed and completely unattractive.
This is something that people consider to be ok when they are on a budget. They feel that logos are not as important as people make them to be and any kind of quick graphic design on Photoshop will do the trick. Then they see the lack of engagement and the low branding power and they regret their decision. This is why investing in a professional logo is very important.