Resist the temptation, because stuffing the laundry will cost you both time and money in the end.
Clothes Won't Get Clean
Clothes need space to agitate in the washer. Fabric rubbing against fabric helps to dislodge dirt. If there's too much laundry in the washer, the spinner will be obstructed and won't spin the fabric as effectively, if at all. The clothes will be compacted and instead of acting as washboards and getting rid of dirt, they'll act as sandpaper and wear out faster. A big load may require you to run an extra rinse cycle to get rid of the detergent, which means using more water and electricity.
Stress on the Washer
Extra laundry puts stress on the washer. The agitator in top-loading machines could break if a full load of clothing gets tangled in its fins. The rotating drum of a front-loading washer can get thrown out of alignment when overloaded. Stressing the washer could break it to the point where fixing it will cost more than replacing it.
Detergent and Water Levels
Overstuffing your laundry may mean you need to add more detergent. The combination of more detergent and less room for clothes to agitate could cause the machine to overflow with suds, water or both. Front-loading washers require special, low-sudsing detergents, so make sure you're using the correct detergent for your washer type. Balance the load size with the proper water level. Too little water and you'll be left with sudsy clothes that need extra rinsing. Too much water and the clothes won't contact each other to dislodge dirt and grime.
Measuring Laundry
Pack clothes loosely in the washer. You shouldn't have to push your clothes into the barrel to make room for more. A small load fills about 1/3 of the machine. A medium load fills about 1/2 of the machine, and a large load fills it about 3/4 full. The most economical way to do laundry is to do it in large loads without overfilling the washer. If you plan to wash only large loads of laundry in categories -- such as whites, darks and delicates -- you will save money, too.