Play to your strengths. If you know you're not one for doing arts and crafts then great that your son goes to nursery where he can do plenty of it and you can do stuff with him that you do want to do.
Arts and crafts and baking are just not my thing. Fortunately it is my husband's thing and he does that kind of stuff with our two from time to time otherwise I knew they were doing that at nursery. My mum would always paint with them when they were younger but I just couldn't be bothered with all the mess.
I prefer playing games and reading with them, I taught them to recognise letters and numbers when they were very young. I read and made up stories for them to help them develop their imagination. I took them out to museums etc, places that interested me so I'd enjoy the trips too.
I love spicy food, so I introduced it to them early and now they're older we regularly go to different places for lunch or dinner, Thai, Indian, Chinese and there's always something they can eat, we've been doing this since they were a couple of years old.
They're rubbish at using cutlery which drives my husband bonkers but for me, it's more important what they eat rather than how they eat so I don't worry about it.
My daughter is very creative, my complete lack of interest in arts and crafts hasn't in any way put her off!
When you left your son pratting about and went downstairs you did the right thing, left him to it and he sorted himself out, you're encouraging him not to be needy, really great if you can do that with a first born, comes naturally with second born but first born tends to be more indulged. Don't cave, being nonchalant is good sometimes.
Relationship between first born sons and mums v complex! They just want to be loved and praised! I can never cuddle my son enough at bedtime, he'd love me to stay with him till he sleeps but for his sake, so he can sleep independently, I have to leave him to it after we've had a snuggle.
When my son was very young he was diagnosed with a life threatening condition, it was devastating for all of us, fortunately the doctor got it wrong and touch loads of wood he's fine. But it did teach me that there is always the unexpected around the corner, the kind of things that really will warrant our fears and worries.
No need for tears after drop off, just plan what you do want to do with him when he's home, even dancing around with him to the radio and having a giggle with him is just as important as sploshing around with paint.
Sounds like you're doing great even by default!