Suction cups are stuck with detergent
If you are annoyed again because no suction cups on the tiles or cabinet doors (kitchen / bathroom) hold, then just try the detergent trick. Distribute a small drop of detergent on the inside of the cup before attaching and then press against the tile.
Wait a moment and you can (for example) hang heavier things on a hook. Has worked with me so far with Haargel. Must be repeated after a few weeks / months.