I used to commute Edinburgh - Glasgow, and plenty of others do the same. It's also common for folk to do the trip just for an evening to go to a gig or something (a lot of tours will have their only Scottish date in Glasgow). I think your friends were probably meaning that you'd need more than a day to fully be able to see what Glasgow has to offer? If not, that seems really odd as it's a busy commuter route.
I used to commute Edinburgh - Glasgow, and plenty of others do the same. It's also common for folk to do the trip just for an evening to go to a gig or something (a lot of tours will have their only Scottish date in Glasgow). I think your friends were probably meaning that you'd need more than a day to fully be able to see what Glasgow has to offer? If not, that seems really odd as it's a busy commuter route.