I started travelling for business almost 3 decades ago (oh boy, am I really that old?).
It was a different time then.The budgets were still available to stay in decent hotels, flights and rental cars. On the other side a lot was more vacation oriented, which made you selecting a Hotel closest to customer and availability of a telephone (yes, normal telephone).
One thing which has transpired over the time was: there is nothing better than the food of your home country. And I do not mean the good stuff – I means the junk food.
For me: Curry Wurst!
What I have traveled around… but the best is still in Cologne.
Pitfalls of Business Travel 