We fell in love with Captiva while vacationing here about 30 years ago.  We were looking for somewhere quiet, different from the east coast of Florida-no high rises or chain stores.  We found it here. You don't have to get in a car all week if you don't want to.  Everything you need is in easy walking distance.   If you want activity-biking, kayaking, tennis, theater, restaurants, shopping it is here.  If you want relaxation, shelling, sunsets, wildlife viewing, lounging and reading, you can have that too. 
We have found this to be a very inviting, friendly island.