Atishoo,
Reading your posts it would seem that you are an extremely nervous passenger and the advice I would give would be to seek out a institution which offers a "Nervous Flyer" program. There are many about and many airlines can put you in touch with those who do the courses.
You have to understand though that the pilots can not be on the PA every time there is a little bump because the nature of flying is that there will always be bumps (just like if you go boating there are always going to be waves). The crew will always inform passengers if they expect bigger bumps than may be normal and this is usually by telling passengers to remain seated with seat belts fastened, and at times for the cabin crew to take their seats and buckle up. But they can not always tell when bumps may be about.
You have to understand we all have our fears but if you want to engage in an activity you need to be proactive in addressing your fears and not expect others to hold your hand every step of the way. There is absolutely no way I'd get on a circus high wire or trapeze, but loved skydiving when I was a youth. If flying proves it is not for you, then like others who have the same fears, you may be best going by bus, as they do. The wife of a good friend absolutely hates flying, and as she ages the more she hates it, to the point where now she just will not travel by air. As she says its because she is a control freak and she is not in control. In fact some of the most white knuckled arm rest grippers you will see in the back of an aircraft are other aircrew, and for much the same reason, they are not in control. As a retired professional pilot myself (not airline though) there have been a couple of times I've had white knuckles when sitting in the back, but when I look at why in the cold light of day, it was for no good reason. Once was driving around a thunderstorm and the other was turbulence - so there you go.
Do the course and then you may be able to sit back and enjoy the magic carpet ride that flying is.
Blue Skies,
Brian