if they're having thoughts you can make it dialogue... and if saying "ladeeladeeda," thought billy joel
is annoying for you, you can just sort of imply it somehow? Dunnot if that makes sense, but I've seen it done well.
but if someone is thinking something serious like, "How the hell did I get here?" and you don't want it to be 'clumsy' the person can just be surprised to find themselves somewhere, or in extreme cases, they can say what they think out loud. But if you want them to think those exact words, there are of course dozens of synonyms for thinking
like, 'a thought suddenly gripped him: "How the hell did I get here?"
'and she thought to herself, "what a wonderful world..."
'suddenly, it came to him, "five and ten are fourteen!"
and more.
personally, I don't think its clunky unless you use the same thing over and over, but its the same as speech, just not directed at anyone. It would be boring if someone wrote he said she said he said she said etc. but you can mix it up or do without them altogether.
ugh sorry this is so long... but... ... ... @ neoeno: the point of view doesn't necessarily make things personal, as I see it. In fact, first person present can be annoying to me, like all these emotions/experiences are being forced upon me. I think its subject matter etc that make things personal, not any tense/point of view. Though those can help.