What you (hopefully) mean: Don’t be intimidated! You can do it!
What they hear: You must be stupid if you can’t do this.
What you say: It’s so simple even a child can figure it out!
What you (hopefully) mean: Calm down and work through it. You’ve got this.
What they hear: Even a child is smarter than you!
Keep in mind that if you’re dealing with someone who is struggling it is self-evidently not easy for them. Claiming that it is invalidates their experience and makes them feel small and stupid. Don’t do that.
What you should say: I get it. This can be pretty intimidating. Let’s work through this together.