expression
apt to think; tend to think
Used to describe a tendency to think or assume something, often with a negative or mistaken connotation. Follows the stem of a verb or a noun.
人は見かけで判断しがちだが、それは思いがちな間違いだ。
People tend to judge by appearances, but that is a mistake they are apt to make.
若いときは、何でも自分でできると思いがちだ。
When you're young, you tend to think you can do everything yourself.
がち is a suffix meaning 'apt to' or 'tend to', attaching to nouns or verb stems. 思いがち is a specific expression combining 思い (thought) with がち.
Compound of 思い (thought) and the suffix がち (apt to, tend to).