I did electronics as well as computing at university. Whilst some of the hands on aspects of electronics were good I didn’t get the same buzz as I did with the way you could use computers to communicate with anyone, anywhere in the world. This just keeps growing where now you can video chat with people from Tube Trains, buses, planes to someone the other side of the world in almost perfect quality.
So I really liked the possibilities of what computing and then cloud computing (where lots of servers with cpu/memory/disks are treated like a big pool of resources so it can look to your application like you have a giant computer)
This is how google/netflix/amazon/dropbox/itunes all got so big is the ability to test out their new great app on one server, but if it really is amazing, then suddenly they can make it work for 1million users really quickly and only pay for what they use.