"It’s easy to see how busy parents would be drawn to sticker charts’ ability to produce quick results. With the right incentives and structure, the system can be an effective way to get kids in the habit of brushing their teeth, for example, or unpacking their school bags. Proponents of sticker charts say that these types of reward systems help prevent power struggles and reduce parents’ need to nag, making the routines of everyday family life easier.
...The problem with sticker charts and similar reward systems is not that they don’t work. Rather, they can work too well, creating significant negative and unintended long-term consequences for both the kids and their families. Sticker charts are powerful psychological tools, and they can go beyond affecting children’s motivation to influence their mindset and even affect their relationship with parents."Source: The Dangers of Using a Sticker Chart to Teach Kids Good Behavior