Still lifes can be highly arranged sets of objects, casual arrangements, or haphazard groupings.
Artists might choose to paint/draw a still life in order to spend time in appreciative contemplation of beautiful plants, flowers, or objects. Sentimentality for old objects might motivate a still life. Objects might be gathered for ironic purposes, pop-culture reference, shock value, or an artist might choose completely random objects to arrange or toss together.
In trompe l'oeil still lifes, some sort of planar surface is convincingly painted facing the viewer, and objects are carefully rendered as if they are attached to or suspended from this surface.
Finally, an artist might choose the still life genre as a vehicle for aesthetic expression, emphasizing abstract shapes, mark making, distortions, palette exploration, etc.
Featured: Fruit Piece by Jan van Huysum.