Curious Siamese cat who always wants to observe everything

I'm going to write this simply because the important thing is to explain the animal well. This Siamese cat has lived with us for almost two years and is probably one of the most curious cats we've ever had. He always wants to know what's going on in the house. If someone opens a cupboard, he immediately appears to look inside. If someone is working or reading, he usually comes over and stays nearby, observing everything. He's not an aggressive or destructive cat, but he is very interested in what people do. The reason for this adoption is that our schedules have changed quite a bit in recent months, and now the apartment is empty for much of the day. We believe that such a sociable cat would be better off in a house with more activity and human presence.