Today City went 3-1 up just after half time and were well on top against the worst side in the league who have some players missing and somehow conspire to lose 4-3. City were slightly on top in the FFA Cup final before Toure scored and they ended up losing 4-0.

In the past City have often managed to lose games where they have been in a dominant position or have gone into games in great form before playing a much weaker side and end up performing poorly and end up losing. 

Why does this keep happening? Discuss.

First loss this year. No idea how you see it as a pattern 

Small club mentality

I'm not talking about this year. I'm talking about the entire history of the club. 

Every time City finally look like a genuine threat for the title they shoot themselves in the foot by losing to weak sides near the bottom of the table or manage to lose a game despite being in a dominant position.

Not enough pork on their fork.

Hire a sports psychologist. Players seem to be more than good enough to win the league.

3 players out today, and a half crocked McLaren

I look at Amor's 15/16 championship AU side, and I saw a team that would often dominate games, but would also often be able to absorb pressure and sustain decent periods of opposition dominance. They would weather the storm without conceding and eventually would find an opening and steal the momentum again. MC know how to go ahead in games and dominate, but they don't know how to cope with teams that they think should be dead and buried finding a second wind and really coming at them. MC seem to be capable of only winning if they completely dominate entire matches. I think they need to learn how to win ugly. This season Adelaide and Sydney FC have been way better than MC at grinding out matches and withstanding opposition dominance without being punished with heaps of goals (eg AU vs NJ, AU vs CCM, SFC vs WP. etc). It's definitely psychological, given they have enough quality to win the league. MC have a weak mentality. 4-0 in the FFA Cup final says it all.    

Some matches that come to mind from the last few seasons.

Round 4 2015/16: Went 2-0 up against the Jets at home before losing 2-3.
Semi-final 2015/16: Smashed 4-1.
Round 15 2016/17: Went 1-0 up against Adelaide in the 4th minute before managing to lose to a side that had only won one match all season.
Round 17 2016/17: Lost to the Jets 2-1 despite going into the match as overwhelming favourites.
Elimination-final 2016/17: Put in a spineless performance against Perth at home and lost 2-0.
Rounds 7 and 8 2017/18: Put in two really bad performances against a horribly out of form Roar side and a severely undermanned Glory side at home. They would have been overwhelming favourites going into these games.
Round 7 2018/19: Lost to Roar despite being overwhelming favourites.
Round 12 2018/19: Lost to CCM who failed to win a match all season up to that point.
Round 23 2018/19: Smashed 3-0 by a side who had zero chance of making the finals.