Kids want two things – to engage deeply and genuinely with parents – and to test and discover the actual limits placed on them.
So, “strictness” is really just consistency. Consistent limits are the walls that hold the secure roof over a child’s head.
And the more mechanical and emotionless the limits and consequences are, the more effective they are in modifying behavior. Any emotional reaction to a child – yes, certainly, “even” anger – reinforces the behavior that triggered it: because kids love to feel the power of deeply affecting a parent, and they need the feeling of deep emotional engagement.
This crucial A,B,C of child-raising is nearly always forgotten, even by the professional experts. It’s best to show only mechanical, perhaps slightly regretful attitudes in imposing consequences. Don’t let unwanted behavior have much emotional effect – not diminishing kindness. And try not to miss any opportunity to praise and reinforce wanted behavior – but take a few moments to look inside and find the deep appreciation such behavior deserves, so kids feel close connection then – compared with mechanical and consistent responses to unwanted behavior.