easygoing
Relaxed and calm, not upset by small problems.
Someone easygoing is relaxed, flexible, and doesn't get upset or worried about small problems. An easygoing teacher might not mind if students need an extra day to finish an assignment, while a strict teacher would insist on the original deadline no matter what. An easygoing friend doesn't complain when plans change at the last minute.
The word describes people who adapt well to unexpected situations and don't create drama over minor inconveniences. If your family is planning a picnic and it starts raining, an easygoing person would cheerfully suggest moving indoors instead of getting frustrated about ruined plans.
Being easygoing doesn't mean being careless or lazy. An easygoing person can still work hard and care about doing things well. They simply don't let stress or small setbacks ruin their mood or their day. They stay calm when things don't go perfectly, making them pleasant to be around. Teachers often describe their best class periods as easygoing when students are cooperative and the day flows smoothly, without tension or conflict.