Have you had a personal bad experience?
What did you do? Did you complain about it or did you try to fix it? The best businesses come from the personal bad experience of their founder(s). Have you used a terrible service and felt you could maybe do a better job? Then there you have a business. Look around you and figure out that one thing that frustrates you so much and very frequently.
There’s a huge chance you’re not the only one experiencing this. If you can fix this problem for yourself, then you can fix it for other people, and there you have a business for yourself. Many entrepreneurs make a common mistake thinking that everything has been done, but the truth is that there is a gap in every market, and you can be the one who bridges it.