We investigate the effects of gemini surfactants, telechelic chains, and lipids on the nature of micelles formed by conventional single-tail surfactants in water by carrying out Monte Carlo simulations. In a mixture of gemini and single-tail surfactants in water, we find direct evidence of micelles of predominantly single-tail surfactants some of which are dynamically cross-linked by gemini surfactants when the concentrations of the geminis are only a few mole percent and their spacers are hydrophilic. In contrast, mixtures of lipids and single-tail surfactants in water form only isolated micelles, each consisting of a mixture of both species, without cross-links.