I had a 600cc bike - have been contemplating a 125 or 250 for pootling to work and back and shorter stuff on.
Its a bit of a tough transition...initially.
We bikers carry a good deal of ego about our choice of transport.
I found the thing to do was separate the function from the aspiration. Which is probably why I kept hold of the big bike for so long.
Consider this...a 125 scooter cost £15 for road fund, is in the tens of pounds for annual insurance, delivers around 60mpg, is as fast through traffic as any big bike (faster in my experience) and never seems to require any maintenance, has loads of storage and heaters too.
Compare that to a 600 cc at 35mpg £hundreds in insurance and more in road fund...let alone sprockets and chains every 10,000 miles and more general maintenance .
Plus no storage or heating.
For a functional commuter, there is no question which is better.
Now fun and thrills, well a scooter is still pretty good and is probably more likely to keep you alive ...and keep your licence.