I’ve had this exact problem with a bistro set on a slightly sloped city sidewalk, and the fix is usually simpler than replacing the furniture. First, figure out which leg is the culprit: put the piece on the pavement, press down gently on each corner, and slide a thin piece of cardboard under the short leg until it stops rocking. That tells you how much correction you need.
For a permanent fix, check whether the furniture has adjustable leveling glides. Many urban outdoor chairs and tables have screw-in feet that twist up or down; turn the short leg out a little at a time until all four points sit firmly. If yours doesn’t, add adjustable furniture feet or leveling pads. Rubber or hard-plastic shims work well because they grip the pavement and won’t slide around like folded paper. For a table, use two shims—one under each short-side leg—so the load stays balanced, and avoid stacking a tall tower of shims; it’s unstable and looks messy.
A quick no-tools option is anti-vibration or felt/rubber pads under the legs. Use thicker pads on the low side, but don’t rely on soft pads alone on very uneven pavement; they can compress and let the wobble come back. If the pavement is really bad, place a small outdoor mat or a thin concrete paver under the whole piece to create a flatter footprint. Make sure the furniture is empty when you level it, then check it again with weight on it.
Finally, tighten any loose bolts or joints—sometimes a wobble is not just the pavement but a slightly loose frame. If the furniture is metal and the legs are hollow, avoid over-tightening adjustable feet, and recheck them after a week. For safety, don’t shim only one corner of a heavy table or bench; distribute the correction and test it by leaning on it. A few minutes with adjustable feet and rubber shims usually makes urban outdoor furniture feel solid again.