The first chapter analyzes an auction setting where an owner of a company delegates bidding to a manager. The owner relies on the manager because only the manager is an expert in the market. The manager's incentives are only partially aligned with the owner. The manager has the incentive to maximize firm profits, but also gains utility from solely winning the auction because he has career concerns. The paper's primary research question is how this setup influences the optimal bidding strategy of a manager in the standard First Price (FPSB) and Second Price (SPSB) auctions. The analysis shows that there is an incentive to overbid in both the FPSB and SPSB auctions. If the owner can punish the manager in the case of a negative profit and does so, the expected price in the FPSB auction is higher than in the SPSB. These results may explain the observation that in many complex auction situations, auctioneers choose FPSB auctions. In the second chapter, we analyze the observation that individuals often prefer to interact with those who want to interact with them. We investigate the effect of such "reciprocal preferences" on matching markets in a laboratory experiment. Matching markets can be unstable when individuals prefer to be matched with a partner who also likes them. We provide evidence that reciprocal preferences exist through a pre-registered and theory-guided laboratory experiment. Individuals, in fact, prefer to be matched with someone who rates them well. We show that this substantially decreases stability in matching markets and investigate underlying motives of reciprocal preferences. The last chapter studies the effect of reciprocal preferenceson stability and truth telling in a theoretical model. We formalize reciprocal preferences, apply them to matching markets, and analyze implications for mechanism design. We show that neither the common Deferred Acceptance mechanism nor any other mechanism is stable in standard two-sided markets. Observing the final allocation of the mechanism enables agents to learn about each other's preferences, which leads to instability. These results contribute to the understanding of non-standard preferences in matching markets and their implications for efficient information and mechanism design.