I tell my couples, weddings bring the worst and best out of people. Some stuff will shock you. People will say and do some things that will make you wonder were you ever really friends. People will turn on you, fall out with you, and more because you didn't do something they wanted.
When choosing your bridal party, do yourself a favor and choose wisely. This is your big day and the time leading up to it will be stressful and full of things to be done. One thing you don't want is for added unnecessary stress to come from the people you asked to be apart of your wedding. You want people around you that will be happy for you, that are going to laugh and cry and jump up and down in glee when you do. You want heartfelt experiences of love surrounding you during this time. If you have any reservations, chances are they’re not the right person. You should be happy and ecstatic to choose your bridal attendants.
You should never feel obligated! Just because you were best friends in grade school and your mom's are still best friends, but you haven't spoken to her in 10 years, does not mean she has to be in the bridal party. Just because his dad gave you your first job and started you in your career that is not grounds for a spot on the team.
Choose the people who you know are genuinely happy for you. The people you want to be around for the next year planning this day, and you know they are going to make it fun. Pick people who are gracious and kind; the ones who will cater to you and not use you. Pick people who you can't fathom doing this without. Pick those people!