3 year old. Do they just not listen?

[SuperlativeOxymoron]

He is an absolute angel for everyone, behaves himself, polite, kind. Everyone loves him and only have positive things to say.

And then he gets home!!!

We had a brilliant established routine, bedtime was simple and easy. But then just recently, he's a nightmare, he tantrums, fights bedtime, even when desperately tired. Up until 2/3 weeks ago he would do as he was told, now he questions us and pushes boundaries.

This evening I was changing a lightbulb, we have glass shades, I put 2 of them on the coffee table after removing them, told ds to leave them alone because one was hot. He touched it and said its cold, dh told him to leave it alone, he was dealing with the dog and I was up a step ladder, so neither of us could get to him fast enough, he then knocked one off the table and smashed it.

What has happened to my lovely little boy? He's become a total horror!! Will he change back?

Most children go through patches when they are working out where the boundaries are. It happens at different ages for different children.

It is also fairly normal for parents to get the poor behaviour - it is where dc relax. There is a subconscious knowledge they are loved by you no matter what.

However, what on earth were you thinking with putting a hot, glass lampshade on a table by a 3 yr old when you were up a ladder ? That is on you .

Thank you @Kite22 a couple of people have said that his behaviour at home is probably that release of emotion within a safe space.

I probably should have said neither was actually hot, I told him one was hot to discourage him.

I accept putting the glass on the table was on me, but previous experience with my son has always been if he's told not to touch something he simply won't.
There are usually mugs of tea/coffee on that table or cups of drink and he doesn't touch them unless they're his, so yes, my lapse of judgement was stupid but it was based on experience of "no don't do that" is listened to.