Where are the GOOD components?

The latest in a long string....
I have a grounded extension cord run out of the garage for some outdoor christmas lights on the fence. At the end of that I have a non-grounded light-sensing receptacle. Into that I have plugged a series of cheap outdoor light strings.

So far so good.

Now, need another extension in another direction to light a tree.

Put pigtail and 3-outlet cube into light-sensor. Then first string of lights into one outlet, another extension cord and tree lights into another.

Well, there is so much wiggle somewhere---everywhere?--- in this stack of plugs, the fence lights go on or off or half-strength; the tree lights go on and off. Also, half that string of 200 mini-lights doesn't light up, right out of the box.

I have receptacles in my kitchen, installed by the last owner, in which the plugs for the Cuisinart and so forth wiggle enough that sometimes the appliances don't work.

Could I be buying better receptacles, cubes, light-sensor receptacles, light strings?

Is it a problem, like "cheap Chinese junk" --- I don't know where anything is made, actually --- from Walmart? Is this prevalent? Are there outdoor Christmas lights made to last more than a few weeks?

What --- and where --- is the good stuff?

TIA for info and opinions.

denno