Excessive expectations are dangerous.
Rice is being produced in surplus in this region.
This dish has too much salt in it.
He reacted excessively to that remark.
過剰 is a more formal, often technical word for excess (e.g. 過剰生産), whereas 余計 is everyday and often carries a critical tone.
過剰 stresses there being too much of something in quantity (e.g. 過剰生産), whereas 過当 stresses that a price, demand, or level of competition has gone beyond a reasonable standard.
過剰 is a more formal, often technical word for excess or overabundance, while 余分 is the everyday word for having more than needed.
過剰 means an excess or surplus of something in a neutral sense, whereas 氾濫 (figurative use) implies things flooding in uncontrollably, often overwhelming or undesirable.
excessive birth rate; overpopulation due to births
hyperconsciousness; excessive self-consciousness; overthinking