Why is a piece of painted furniture still kind of tacky three weeks after being painted?

I think the paint actually isn’t dry.
It could be that the ground lair(s) weren’t totally dry/hard before the regular was put, or the regular has not been properly stirred before applying, thus the siccative/drying agent wasn’t well mixed although I am not totally sure if that is true or a myth, or the location of the paint job was too cold (under a certain temperature we were not allowed to paint I think it was 5 Celsius).
Three weeks is already pretty long, but it happens sometimes that certain paints take ‘forever’ to get totally dry, and hard.
This is all knowledge that I gained from hear-say, so it could be that other Jellies have more accurate explanations.

I agree with @rebbel. And, my guess for it not drying is because it isn’t wood. If it was smooth, even with primer, it most likely needed to be given a “tooth” prior to painting. (It needed to be sanded so the paint would adhere better).

What type of paint did your painter use? Latex or oil based and interior or exterior paint will make a difference in drying times and feel of the paint when dry.

In humid weather it would take at least that long. Maybe try using a hair dryer set on low.

I’m with @rebbel – he said everything I was going to say. I bet the primers weren’t dry and the paint wasn’t stirred properly! It might have to be sanded down and started over. But give it some more time first. Is it in a heated area? I would put it as close to a heat source as possible and see if that helps.

Is it semi-gloss or gloss? Those tend to stay tacky more often than flat or eggshell.

I asked this question in early January, and it’s now end of May and things that I have on this bookcase are sticking to it and pulling off little bits of paint when I pick them up. I can’t have it repainted because it’s been painted by my job, so I kind of have to take what I was given. However, if I ever had this thing in my house, it would probably have to be stripped and redone.

@jca I would suggest buyIng a thick piece of clear plastic at the fabric store, cutting to fit the bottom of the shelf, and that way the books and other things on there won’t stick and it won’t change the look of the bookcase.