Hey hi , on feb 2010 when I woke up in the middle of the night around 3:30. I felt that the bed was shaking,and I saw everything shaking, the room, the walls, my glass of water. That was horrible.
Only once as they are rare in the UK. I was in bed when the bed lurched a good 6" from the wall, which takes some doing as it's made of metal! Not scary so much as a shock.
If you go to Japan, you will experience them all the time. Japan has many earthquakes happen. Although they are really small in scale, they happen on a regular basis. Tokyo is long due for a disastrous earthquake in the next few years so just be careful when you go there.