Why do I do this to myself?

I try workout atleast 4 times a week. I generally avoid Wednesday at my gym. This week, decided I should not do so and went in. 50 minutes of kicking, punching, squatting, lunging, resistance training!! Next day my butt was sore! It hurt so much. A sane person might have rested….but telling myself that determination and perseverance helps, I went for working out. Another 50 minutes of gruelling work out. Icing to the cake, had to do some grocery after the work out (I know ! yuck!!still…) I park the car in the driveway and could not get out. With great difficult lugged my shopping and myself to the door. I just wanted to sit in my doorway not wanting to climb the steps to get into my home!! Today my hamstring muscles, I think, are on a strike. They don’t want me do anything! Thank God! Today is a rest day - no workout!
Now why do I do this to myself? I found out I was not alone in enduring this pain…all those who came to the work out (including the instructor) were sore! LOL! That set me thinking why any of us do this?
I started this because I wanted to lose weight. Get to the weight I was when I got married ( a Herculean task I might add) My family has been supportive and they do tell me that I should do it for myself and not to fit into those jeans! “Friends” remarking that I could lose a few pounds or that I look “chubby” would send me into those spiralling depression moments(?!?). Decided I must do something about it and embarked on this.
The work out has been great though. I should thank people who unknowingly have pushed me into this. It is a stress reliever !! Hope it helps finally in my pursuit.
Then again to the question…is it worth the pain? Is it worth pushing oneself? Why am I really doing this? For me? To look like those models who wear skinny jeans and look fabulous? For people around me??
I know the answer should be for me to be healthy, look and feel good. ..but who am I kidding? Again it boils down to being accepted and appreciated by those around us right? Am I alone in this thought?