Since I left the world of education, my usual breakfast has been a cereal bar, occasionally with biscuits. That's it. Heck, my breakfast is later than 2pm as my sleep has been messed up since early July. It's improving, though.
When I was a student, though, I'd have a proper breakfast on weekdays. Microwave porridge with honey and a mug of warm sweetened milk (or coffee). 2 or 3 pieces of toast with Nutella/strawberry jam (I'd need something to eat between that and lunch because I'd find myself quite hungry). An egg sandwich (break the yolks first to avoid a mess) with a mug of herbal tea in milk. Scrambled eggs with a hot drink (you can see the milk/coffee theme). If I was running a bit late, I'd make myself a hot drink (sweetened milk/coffee) and pick up one or two cereal bars to eat during my journey.
I need to have something to drink with my breakfast because I have to take medicine in the mornings and evenings and hot drinks (and thick juices such as mango or guava) go down with my tablets much better than drinks such as water and squash. If I have water or squash with my tablets, I find that they're more likely to not go down my throat well which ends up in a horrible taste in my mouth (from my tablets) that's hard to get rid of.
[[I wouldn't call this easy or fast as it's a hearty breakfast you have with your family but I thought I'd add it anyway]] There's the occasional weekend (maybe once a month) where my family and I have a special Pakistani breakfast called Halwa Puri (we get it from one of the nearby Asian confectioners). Halwa is a sweet food that often has raisins and/or nuts added. Puri is a fried type of bread. We have Halwa Puri with chickpea masala, potato bhaji and maybe a little bit of pickle. Here's a photo of Halwa Puri:
Stack of puris on the left, halwa on the right (in the dish with a spoon) and chickpea masala in the centre.
Halwa Puri is so delicious that it could make me forget about my worries for a while. It's wonderful!