What being a vessel means

To the Jews I became as a Jew, in order to win Jews. To those under the law I became as one under the law (though not being myself under the law) that I might win those under the law. 21 To those outside the law I became as one outside the law (not being outside the law of God but under the law of Christ) that I might win those outside the law. 22 To the weak I became weak, that I might win the weak. I have become all things to all people, that by all means I might save some. 23 I do it all for the sake of the gospel, that I may share with them in its blessings.
1 Corinthians 9:20-23

I suppose that one struggle I face in service is the question of "what is left for me?" 

If we supposed to love others it does seem to follow that we very well end up living for them. This is such an offensive thought to me. How can it be that God wants me to live in a manner which leaves nothing left for myself? 

But actually this is nothing fresh. 

The bible describes Christians as living sacrifices (our lives wholly dedicated to God), or as vessels, existing only for the purposes of the owner. 

1 Corinthians 9:20-23 illustrates this even more vividly. Here Paul says he becomes whatever he needs to become to reach people. To the Jews he became as a Jew, to the weak he became weak. In these 3 verses there is a distinct lack of self-definition. Paul was not truly defined by any of those traits, but they were taken on or accentuated to serve the purpose of reaching out to people. 

At the core of these shifting identities was a life that was dedicated to the service of others. Paul didn't let any of these things define him. His identity was already secure as a Disciple of Christ, a Child of God, Elect, Chosen. The rest didn't matter that much anymore, they became merely tools in his hands, tools he used skilfully to fulfil his calling as a Christian. 

As the number of things to do this year pile up mercilessly, I want to choose to be as Paul. I shall be all things to all men, essentially formless and at God's disposal to shape into the appropriate tools for His work. Let me not bargain or resist. Let me be a vessel. 

On the unnatural-ness of heterosexuality

For a long time I've been thinking that if God was opposed to homosexuality why did He make heterosexuality so flimsy?
I was thinking that if I spent too much time in guys or if I were brought up in a boys' school without any contact with girls there's a real high chance that I would've been gay.

The things that we learn in school about gender being a socially constructed thing... Well, I kinda buy into it too. I'm not the sort of Christian who would insist that there is some sort of "naturalness" to heterosexuality, in fact, it seems like it is rather natural for people to simply do whatever they please and choose whomever they want.

What is my response to this? I think that God has left it as such so that we can Honour Him through our conscious, effortful strive towards a particular sort of gender. Men to Honour Him by striving towards masculinity and women by striving towards femininity (something like that).

Because it is so "un-natural", it is so intentional. Because it is so intentional, it can be an act of worship.
Certainly it is harder then, for some people to worship God through their gender and sexuality. But in the same way, some struggle to worship Him in keeping their hands and eyes to themselves.